diff --git a/.github/workflows/cd.yaml b/.github/workflows/cd.yaml
index bd348d24..4c82c521 100644
--- a/.github/workflows/cd.yaml
+++ b/.github/workflows/cd.yaml
@@ -57,6 +57,11 @@ jobs:
     name: "Pre-flight Check"
     runs-on: [self-hosted, harbor, k8s]
     timeout-minutes: 1
+    # 2026-03-29: Runner 全局 mutex，確保同一 Runner 不會並行執行任何 CD Job
+    # 使用固定 group 名稱 (非 run_id)，所有 CD Jobs 共用同一把鎖
+    concurrency:
+      group: runner-awoooi-cd-mutex
+      cancel-in-progress: false
     steps:
       # =======================================================================
       # 2026-03-29: Runner _diag/pages 檔案衝突修復 (v3)
@@ -130,6 +135,9 @@ jobs:
     runs-on: [self-hosted, harbor, k8s]
     needs: pre-flight-check
     timeout-minutes: 1
+    concurrency:
+      group: runner-awoooi-cd-mutex
+      cancel-in-progress: false
     outputs:
       api: ${{ inputs.force_deploy == true && 'true' || steps.filter.outputs.api }}
       web: ${{ inputs.force_deploy == true && 'true' || steps.filter.outputs.web }}
@@ -168,7 +176,10 @@ jobs:
     name: "Build API"
     runs-on: [self-hosted, harbor, k8s]
     needs: detect-changes
-    timeout-minutes: 20  # 2026-03-29: 增加超時時間 (Docker Build 需要更長時間)
+    timeout-minutes: 20
+    concurrency:
+      group: runner-awoooi-cd-mutex
+      cancel-in-progress: false
     if: |
       !inputs.skip_api && (
         needs.detect-changes.outputs.api == 'true' ||
@@ -208,7 +219,10 @@ jobs:
     name: "Build Web"
     runs-on: [self-hosted, harbor, k8s]
     needs: detect-changes
-    timeout-minutes: 20  # 2026-03-29: 增加超時時間 (Next.js Build 需要更長時間)
+    timeout-minutes: 20
+    concurrency:
+      group: runner-awoooi-cd-mutex
+      cancel-in-progress: false
     if: |
       !inputs.skip_web && (
         needs.detect-changes.outputs.web == 'true' ||
@@ -261,6 +275,9 @@ jobs:
     runs-on: [self-hosted, harbor, k8s]
     needs: [detect-changes, build-api, build-web]
     timeout-minutes: 10
+    concurrency:
+      group: runner-awoooi-cd-mutex
+      cancel-in-progress: false
     if: always() && (needs.build-api.result == 'success' || needs.build-api.result == 'skipped') && (needs.build-web.result == 'success' || needs.build-web.result == 'skipped')
     environment: production
     steps: