diff --git a/apps/api/src/api/v1/approvals.py b/apps/api/src/api/v1/approvals.py
index c410cb8f..603a8d55 100644
--- a/apps/api/src/api/v1/approvals.py
+++ b/apps/api/src/api/v1/approvals.py
@@ -25,13 +25,23 @@ import re
 from typing import TYPE_CHECKING
 from uuid import UUID
 
-from fastapi import APIRouter, BackgroundTasks, Depends, Header, HTTPException, status
-
 if TYPE_CHECKING:
     from src.services.notifications import ExecutionStatus
 
+from fastapi import (
+    APIRouter,
+    BackgroundTasks,
+    Depends,
+    Header,
+    HTTPException,
+    Request,
+    status,
+)
+from fastapi.responses import StreamingResponse
+
 from src.core.config import settings
 from src.core.logging import get_logger
+from src.core.sse import EventType, SSEEvent, get_publisher
 from src.models.approval import (
     ApprovalRequest,
     ApprovalRequestCreate,
@@ -521,6 +531,9 @@ async def create_approval(
         required_signatures=approval.required_signatures,
     )
 
+    # SSE: 發布建立事件
+    asyncio.create_task(_publish_approval_event("created", approval))
+
     return ApprovalRequestResponse.from_approval(approval)
 
 
@@ -667,6 +680,10 @@ async def sign_approval(
                 note="Approval has no incident_id in metadata, cannot update Incident status",
             )
 
+    # SSE: 發布簽核/核准事件
+    event_action = "approved" if execution_triggered else "signed"
+    asyncio.create_task(_publish_approval_event(event_action, approval))
+
     return SignResponse(
         success=True,
         message=message,
@@ -752,4 +769,129 @@ async def reject_approval(
         reason=request.reason,
     )
 
+    # SSE: 發布拒絕事件
+    asyncio.create_task(_publish_approval_event("rejected", approval))
+
     return ApprovalRequestResponse.from_approval(approval)
+
+
+# =============================================================================
+# SSE Event Publishing (Phase 15: Polling → SSE)
+# =============================================================================
+
+async def _publish_approval_event(
+    action: str,
+    approval: ApprovalRequest,
+) -> None:
+    """
+    發布 Approval SSE 事件
+
+    Args:
+        action: 事件動作 (created, signed, approved, rejected, executed)
+        approval: 授權請求物件
+    """
+    try:
+        pub = await get_publisher()
+
+        event = SSEEvent(
+            type=EventType.APPROVAL,
+            data={
+                "action": action,
+                "approval_id": str(approval.id),
+                "status": approval.status.value,
+                "risk_level": approval.risk_level.value,
+                "current_signatures": approval.current_signatures,
+                "required_signatures": approval.required_signatures,
+                "action_text": approval.action[:100],
+            },
+        )
+
+        sent_count = await pub.publish(event, topic="approvals")
+
+        if sent_count > 0:
+            logger.debug(
+                "approval_sse_published",
+                action=action,
+                approval_id=str(approval.id),
+                sent_count=sent_count,
+            )
+
+    except Exception as e:
+        logger.error(
+            "approval_sse_publish_failed",
+            action=action,
+            approval_id=str(approval.id),
+            error=str(e),
+        )
+
+
+# =============================================================================
+# GET /api/v1/approvals/stream (SSE)
+# =============================================================================
+
+@router.get(
+    "/stream",
+    summary="SSE 即時授權更新",
+    description="Server-Sent Events 即時推送授權狀態變更，取代輪詢機制",
+)
+async def stream_approvals(request: Request) -> StreamingResponse:
+    """
+    SSE 即時授權更新 (Phase 15: Polling → SSE)
+
+    事件類型:
+    - connected: 連線建立
+    - heartbeat: 心跳 (每 15 秒)
+    - approval: 授權狀態變更 (created, signed, approved, rejected, executed)
+
+    Client Usage (JavaScript):
+    ```javascript
+    const es = new EventSource('/api/v1/approvals/stream');
+    es.addEventListener('approval', (e) => {
+        const data = JSON.parse(e.data);
+        console.log('Approval update:', data.action, data.approval_id);
+        // Refresh approval list or update specific item
+    });
+    es.addEventListener('heartbeat', () => {
+        console.log('Connection alive');
+    });
+    ```
+    """
+    logger.info(
+        "approval_stream_connect",
+        client_ip=request.client.host if request.client else "unknown",
+    )
+
+    pub = await get_publisher()
+
+    # 訂閱 approvals topic
+    client = await pub.subscribe(
+        topics=["approvals"],
+        metadata={"ip": request.client.host if request.client else "unknown"},
+    )
+
+    async def event_generator():
+        """SSE 事件生成器，含斷線偵測"""
+        try:
+            async for data in pub.stream(client):
+                if await request.is_disconnected():
+                    logger.info("approval_stream_disconnected", client_id=client.id)
+                    break
+                yield data
+
+        except asyncio.CancelledError:
+            logger.info("approval_stream_cancelled", client_id=client.id)
+            raise
+
+        finally:
+            logger.info("approval_stream_cleanup", client_id=client.id)
+
+    return StreamingResponse(
+        event_generator(),
+        media_type="text/event-stream",
+        headers={
+            "Cache-Control": "no-cache, no-store, must-revalidate",
+            "Connection": "keep-alive",
+            "X-Accel-Buffering": "no",
+            "Access-Control-Allow-Origin": "*",
+        },
+    )
diff --git a/apps/web/src/components/ai/ai-command-panel.tsx b/apps/web/src/components/ai/ai-command-panel.tsx
index 0f3682d8..5a204644 100644
--- a/apps/web/src/components/ai/ai-command-panel.tsx
+++ b/apps/web/src/components/ai/ai-command-panel.tsx
@@ -8,13 +8,12 @@
  * Features:
  * - OpenClaw AI 視覺化 (頂部)
  * - 待授權卡片列表 (底部)
- * - 即時輪詢後端待簽核
+ * - **Phase 15: SSE 即時更新** (取代輪詢)
  * - Nothing.tech 純白極簡風格
  *
  * i18n: 100% next-intl
  */
 
-import { useEffect } from 'react'
 import { useTranslations } from 'next-intl'
 import { cn } from '@/lib/utils'
 import { OpenClawPanel, type OpenClawStatus } from './openclaw-panel'
@@ -24,6 +23,7 @@ import {
   usePendingApprovals,
   toFrontendApproval,
 } from '@/stores/approval.store'
+import { useApprovalSSE } from '@/hooks/useApprovalSSE'
 import { ShieldCheck, Bell } from 'lucide-react'
 
 // =============================================================================
@@ -43,14 +43,11 @@ export function AICommandPanel({ className }: AICommandPanelProps) {
   const tApproval = useTranslations('approval')
 
   // Store
-  const { fetchPending, signApproval, rejectApproval, startPolling, stopPolling } = useApprovalStore()
+  const { fetchPending, signApproval, rejectApproval } = useApprovalStore()
   const pendingApprovals = usePendingApprovals()
 
-  // Start polling on mount
-  useEffect(() => {
-    startPolling(5000) // Poll every 5 seconds
-    return () => stopPolling()
-  }, [startPolling, stopPolling])
+  // Phase 15: SSE 即時更新 (取代輪詢)
+  useApprovalSSE({ autoConnect: true })
 
   // Handle approval
   const handleApprove = async (id: string) => {
diff --git a/apps/web/src/components/ai/hitl-section.tsx b/apps/web/src/components/ai/hitl-section.tsx
index b7a261c7..c11ac56bb 100644
--- a/apps/web/src/components/ai/hitl-section.tsx
+++ b/apps/web/src/components/ai/hitl-section.tsx
@@ -9,10 +9,10 @@
  * - OpenClaw AI 思考流視覺化
  * - 動態 Approval Card 渲染 (100% 後端資料)
  * - Slide Up 動畫過渡
- * - 即時輪詢後端待簽核列表
+ * - **Phase 15: SSE 即時更新** (取代輪詢)
  */
 
-import { useState, useEffect, useCallback } from 'react'
+import { useState, useCallback } from 'react'
 import { useTranslations } from 'next-intl'
 import { cn } from '@/lib/utils'
 import { OpenClawPanel, type OpenClawStatus } from './openclaw-panel'
@@ -22,6 +22,7 @@ import {
   usePendingApprovals,
   toFrontendApproval,
 } from '@/stores/approval.store'
+import { useApprovalSSE } from '@/hooks/useApprovalSSE'
 import { useTimelineStore } from '@/stores/timeline.store'
 import { ActionTimeline } from '@/components/timeline'
 import { GlassCard, GlassCardTitle, GlassCardContent, GlassCardHeader } from '@/components/ui/glass-card'
@@ -84,10 +85,13 @@ export function HITLSection({ locale, className }: HITLSectionProps) {
   const tApproval = useTranslations('approval')
 
   // Store
-  const { fetchPending, signApproval, rejectApproval, startPolling, stopPolling } = useApprovalStore()
+  const { fetchPending, signApproval, rejectApproval } = useApprovalStore()
   const pendingApprovals = usePendingApprovals()
   const addTimelineEvent = useTimelineStore((state) => state.addEvent)
 
+  // Phase 15: SSE 即時更新 (取代輪詢)
+  useApprovalSSE({ autoConnect: true })
+
   // AI thinking state
   const [openclawStatus, setClawbotStatus] = useState<OpenClawStatus>('patrolling')
   const [currentAlertType, setCurrentAlertType] = useState<string | undefined>()
@@ -105,12 +109,6 @@ export function HITLSection({ locale, className }: HITLSectionProps) {
     requiredRoles: string
   } | null>(null)
 
-  // Start polling on mount
-  useEffect(() => {
-    startPolling(5000) // Poll every 5 seconds
-    return () => stopPolling()
-  }, [startPolling, stopPolling])
-
   // Simulate webhook alert (triggers AI thinking flow)
   const simulateAlert = useCallback(async (alertType: string, severity: 'critical' | 'warning') => {
     setIsSimulating(true)
diff --git a/apps/web/src/components/approval/live-approval-panel.tsx b/apps/web/src/components/approval/live-approval-panel.tsx
index b38aec2c..de4f7031 100644
--- a/apps/web/src/components/approval/live-approval-panel.tsx
+++ b/apps/web/src/components/approval/live-approval-panel.tsx
@@ -6,7 +6,7 @@
  * 整合後端 API 的 Multi-Sig 授權流程
  *
  * Features:
- * - 輪詢 GET /api/v1/approvals/pending
+ * - **Phase 15: SSE 即時更新** (取代輪詢)
  * - 真實 API 簽核與拒絕
  * - Multi-Sig 狀態即時更新
  * - 簽核成功動畫
@@ -15,9 +15,10 @@
  *   - DevOps 角色長按時顯示 Access Denied
  */
 
-import { useEffect, useState, useCallback } from 'react'
+import { useState, useCallback } from 'react'
 import { useTranslations } from 'next-intl'
 import { useApprovalStore, usePendingApprovals, toFrontendApproval } from '@/stores/approval.store'
+import { useApprovalSSE } from '@/hooks/useApprovalSSE'
 import { ApprovalCard, type ApprovalRequest, type RiskLevel } from './approval-card'
 import {
   GlassCard,
@@ -101,9 +102,12 @@ export function LiveApprovalPanel({
   const t = useTranslations('approval')
   const tCommon = useTranslations('common')
 
-  const { startPolling, stopPolling, signApproval, rejectApproval, error } = useApprovalStore()
+  const { signApproval, rejectApproval, error } = useApprovalStore()
   const pendingApprovals = usePendingApprovals()
 
+  // Phase 15: SSE 即時更新 (取代 Polling)
+  const { isConnected, status: sseStatus } = useApprovalSSE({ autoConnect: true })
+
   // 模擬當前登入者 (Phase 3 權限擋板)
   const currentUser: CurrentUser = {
     id: signerId,
@@ -123,12 +127,6 @@ export function LiveApprovalPanel({
     requiredRoles: string
   } | null>(null)
 
-  // Start polling on mount
-  useEffect(() => {
-    startPolling(5000)
-    return () => stopPolling()
-  }, [startPolling, stopPolling])
-
   // Handle sign with permission check (Phase 3 權限擋板)
   const handleSign = useCallback(async (id: string, riskLevel: RiskLevel) => {
     // Phase 3: 權限檢查
diff --git a/apps/web/src/hooks/index.ts b/apps/web/src/hooks/index.ts
index 53e01145..cf2b2660 100644
--- a/apps/web/src/hooks/index.ts
+++ b/apps/web/src/hooks/index.ts
@@ -1,5 +1,6 @@
 export * from './use-agent'
 export * from './use-health'
 export * from './useSSE'
+export * from './useApprovalSSE'
 export * from './useIncidents'
 export * from './useGlobalPulseMetrics'
diff --git a/apps/web/src/hooks/useApprovalSSE.ts b/apps/web/src/hooks/useApprovalSSE.ts
new file mode 100644
index 00000000..f9c5cc1b
--- /dev/null
+++ b/apps/web/src/hooks/useApprovalSSE.ts
@@ -0,0 +1,86 @@
+'use client'
+
+/**
+ * useApprovalSSE - Approval SSE 連線 Hook
+ * ========================================
+ * Phase 15: Polling → SSE
+ *
+ * 自動管理 SSE 連線生命週期:
+ * - 組件掛載時自動連線
+ * - 組件卸載時自動斷線
+ * - 支援 SSE 失敗後降級到 Polling
+ */
+
+import { useEffect, useRef, useCallback } from 'react'
+import { useApprovalStore } from '@/stores/approval.store'
+
+interface UseApprovalSSEOptions {
+  /** 自動連線 (預設 true) */
+  autoConnect?: boolean
+  /** SSE 失敗後是否降級到 Polling (預設 true) */
+  fallbackToPolling?: boolean
+}
+
+interface UseApprovalSSEReturn {
+  /** SSE 連線狀態 */
+  status: 'disconnected' | 'connecting' | 'connected' | 'reconnecting' | 'error'
+  /** 是否已連線 */
+  isConnected: boolean
+  /** 是否重連中 */
+  isReconnecting: boolean
+  /** 錯誤訊息 */
+  error: string | null
+  /** 手動連線 */
+  connect: () => void
+  /** 手動斷線 */
+  disconnect: () => void
+}
+
+export function useApprovalSSE(options: UseApprovalSSEOptions = {}): UseApprovalSSEReturn {
+  const { autoConnect = true, fallbackToPolling = true } = options
+
+  const connectSSE = useApprovalStore((s) => s.connectSSE)
+  const disconnectSSE = useApprovalStore((s) => s.disconnectSSE)
+  const stopPolling = useApprovalStore((s) => s.stopPolling)
+  const sseStatus = useApprovalStore((s) => s.sseStatus)
+  const error = useApprovalStore((s) => s.error)
+
+  const mountedRef = useRef(true)
+
+  const handleConnect = useCallback(() => {
+    if (!mountedRef.current) return
+    console.log('[useApprovalSSE] Connecting...')
+    connectSSE()
+  }, [connectSSE])
+
+  const handleDisconnect = useCallback(() => {
+    console.log('[useApprovalSSE] Disconnecting...')
+    disconnectSSE()
+    stopPolling()
+  }, [disconnectSSE, stopPolling])
+
+  useEffect(() => {
+    mountedRef.current = true
+
+    if (autoConnect) {
+      console.log('[useApprovalSSE] Auto-connecting...')
+      handleConnect()
+    }
+
+    // Cleanup: 防止殭屍連線
+    return () => {
+      console.log('[useApprovalSSE] Cleanup')
+      mountedRef.current = false
+      handleDisconnect()
+    }
+  }, [autoConnect, handleConnect, handleDisconnect])
+
+  return {
+    status: sseStatus,
+    isConnected: sseStatus === 'connected',
+    isReconnecting: sseStatus === 'reconnecting',
+    error,
+    connect: handleConnect,
+    disconnect: handleDisconnect,
+  }
+}
diff --git a/apps/web/src/stores/approval.store.ts b/apps/web/src/stores/approval.store.ts
index dc7ac125..d98e7da0 100644
--- a/apps/web/src/stores/approval.store.ts
+++ b/apps/web/src/stores/approval.store.ts
@@ -74,6 +74,8 @@ export interface SignResponse {
 // Store State
 // =============================================================================
 
+type SSEConnectionStatus = 'disconnected' | 'connecting' | 'connected' | 'reconnecting' | 'error'
+
 interface ApprovalState {
   // Data
   pendingApprovals: ApprovalRequest[]
@@ -89,13 +91,21 @@ interface ApprovalState {
   recentlyApproved: Set<string>
   recentlyRejected: Set<string>
 
-  // Polling
+  // SSE Connection (Phase 15: Polling → SSE)
+  sseStatus: SSEConnectionStatus
+  sseReconnectAttempts: number
+
+  // Polling (Legacy, kept for fallback)
   pollingInterval: number | null
 
   // Actions
   fetchPending: () => Promise<void>
   signApproval: (id: string, signerId: string, signerName: string, comment?: string) => Promise<SignResponse | null>
   rejectApproval: (id: string, rejectorId: string, rejectorName: string, reason: string) => Promise<boolean>
+  // SSE Actions (Phase 15)
+  connectSSE: () => void
+  disconnectSSE: () => void
+  // Polling (Legacy)
   startPolling: (intervalMs?: number) => void
   stopPolling: () => void
   clearRecentlyResolved: (id: string) => void
@@ -107,6 +117,9 @@ interface ApprovalState {
 // =============================================================================
 
 const DEFAULT_POLLING_INTERVAL = 5000 // 5 seconds
+const MAX_SSE_RECONNECT_ATTEMPTS = 10
+const BASE_RECONNECT_DELAY = 1000 // 1 second
+const MAX_RECONNECT_DELAY = 30000 // 30 seconds
 
 // 統帥鐵律: 禁止任何 Fallback IP
 const getApiBaseUrl = (): string => {
@@ -126,6 +139,8 @@ const API_BASE_URL = getApiBaseUrl()
 // =============================================================================
 
 let pollingTimer: NodeJS.Timeout | null = null
+let eventSource: EventSource | null = null
+let sseReconnectTimeout: NodeJS.Timeout | null = null
 
 export const useApprovalStore = create<ApprovalState>()(
   subscribeWithSelector((set, get) => ({
@@ -138,6 +153,10 @@ export const useApprovalStore = create<ApprovalState>()(
     rejectingId: null,
     recentlyApproved: new Set(),
     recentlyRejected: new Set(),
+    // SSE state (Phase 15)
+    sseStatus: 'disconnected',
+    sseReconnectAttempts: 0,
+    // Polling (Legacy)
     pollingInterval: null,
 
     // ==========================================================================
@@ -324,7 +343,122 @@ export const useApprovalStore = create<ApprovalState>()(
     },
 
     // ==========================================================================
-    // Polling
+    // SSE Connection (Phase 15: Polling → SSE)
+    // ==========================================================================
+    connectSSE: () => {
+      const state = get()
+
+      // Already connected or connecting
+      if (eventSource && state.sseStatus === 'connected') {
+        console.log('[Approval SSE] Already connected')
+        return
+      }
+
+      // Clean up existing connection
+      if (eventSource) {
+        eventSource.close()
+        eventSource = null
+      }
+
+      if (!API_BASE_URL) {
+        console.error('[Approval SSE] Missing API URL')
+        set({ sseStatus: 'error', error: 'Missing API URL' })
+        return
+      }
+
+      set({ sseStatus: 'connecting', error: null })
+      console.log('[Approval SSE] Connecting to', `${API_BASE_URL}/api/v1/approvals/stream`)
+
+      // Initial fetch
+      state.fetchPending()
+
+      // Create EventSource
+      eventSource = new EventSource(`${API_BASE_URL}/api/v1/approvals/stream`)
+
+      eventSource.onopen = () => {
+        console.log('[Approval SSE] Connected')
+        set({
+          sseStatus: 'connected',
+          sseReconnectAttempts: 0,
+          error: null,
+        })
+      }
+
+      // Handle approval events
+      eventSource.addEventListener('approval', (e: MessageEvent) => {
+        try {
+          const data = JSON.parse(e.data)
+          console.log('[Approval SSE] Event:', data.action, data.approval_id)
+
+          // Re-fetch pending approvals on any change
+          get().fetchPending()
+
+        } catch (err) {
+          console.error('[Approval SSE] Failed to parse event:', err)
+        }
+      })
+
+      eventSource.addEventListener('heartbeat', () => {
+        console.log('[Approval SSE] Heartbeat')
+      })
+
+      eventSource.addEventListener('connected', () => {
+        console.log('[Approval SSE] Server confirmed connection')
+      })
+
+      // Error handling with exponential backoff
+      eventSource.onerror = () => {
+        const attempts = get().sseReconnectAttempts
+
+        if (attempts >= MAX_SSE_RECONNECT_ATTEMPTS) {
+          console.error('[Approval SSE] Max reconnect attempts reached, falling back to polling')
+          set({ sseStatus: 'error', error: 'SSE connection failed' })
+          eventSource?.close()
+          eventSource = null
+          // Fallback to polling
+          get().startPolling()
+          return
+        }
+
+        set({
+          sseStatus: 'reconnecting',
+          sseReconnectAttempts: attempts + 1,
+        })
+
+        const delay = Math.min(
+          BASE_RECONNECT_DELAY * Math.pow(2, attempts),
+          MAX_RECONNECT_DELAY
+        )
+
+        console.log(`[Approval SSE] Reconnecting in ${delay}ms (attempt ${attempts + 1})`)
+
+        if (sseReconnectTimeout) clearTimeout(sseReconnectTimeout)
+        sseReconnectTimeout = setTimeout(() => {
+          eventSource?.close()
+          eventSource = null
+          get().connectSSE()
+        }, delay)
+      }
+    },
+
+    disconnectSSE: () => {
+      console.log('[Approval SSE] Disconnecting')
+
+      if (eventSource) {
+        eventSource.close()
+        eventSource = null
+      }
+
+      if (sseReconnectTimeout) {
+        clearTimeout(sseReconnectTimeout)
+        sseReconnectTimeout = null
+      }
+
+      set({ sseStatus: 'disconnected', sseReconnectAttempts: 0 })
+    },
+
+    // ==========================================================================
+    // Polling (Legacy Fallback)
     // ==========================================================================
     startPolling: (intervalMs = DEFAULT_POLLING_INTERVAL) => {
       const state = get()
@@ -396,6 +530,13 @@ export const useIsRejectingApproval = (id: string) =>
 export const useApprovalError = () =>
   useApprovalStore((state) => state.error)
 
+// SSE Status Hooks (Phase 15)
+export const useApprovalSSEStatus = () =>
+  useApprovalStore((state) => state.sseStatus)
+
+export const useApprovalSSEConnected = () =>
+  useApprovalStore((state) => state.sseStatus === 'connected')
+
 // =============================================================================
 // Type Converters (Backend → Frontend)
 // =============================================================================