diff --git a/src/api/toolchain_routes.py b/src/api/toolchain_routes.py
index 4aa467c..c6a09dd 100644
--- a/src/api/toolchain_routes.py
+++ b/src/api/toolchain_routes.py
@@ -265,7 +265,8 @@ async def _handle_pull_request(payload: Dict[str, Any]) -> None:
         await _handle_pr_opened(payload)
     elif action == "synchronize":
         await _handle_pr_synchronize(payload)
-    # 其他 action 忽略
+    elif action == "closed":
+        await _handle_pr_closed(payload)
 
 
 async def _handle_pr_opened(payload: Dict[str, Any]) -> None:
@@ -434,9 +435,9 @@ async def _handle_pr_synchronize(payload: Dict[str, Any]) -> None:
     # 查询最近 review 的提交者
     reviewer = await _fetch_latest_reviewer(repo, pr_number)
     if not reviewer:
-        # 没有 review 历史，跳过（opened 事件已经通知过）
-        logger.debug("No review history for PR #%s, skipping synchronize notification", pr_number)
-        return
+        # 没有已有 review 历史，fallback 到默认 reviewer
+        reviewer = "simayi-challenger"
+        logger.info("No review history for PR #%s, using default reviewer %s", pr_number, reviewer)
 
     text = render_template("review_updated", {
         "repo": repo,
@@ -451,6 +452,38 @@ async def _handle_pr_synchronize(payload: Dict[str, Any]) -> None:
     _send_mail(reviewer, title, text)
 
 
+async def _handle_pr_closed(payload: Dict[str, Any]) -> None:
+    """PR closed → 如果 merged，通知 PR 作者。"""
+    pr = payload.get("pull_request")
+    if not pr or not isinstance(pr, dict):
+        return
+
+    # 只处理 merged 的 PR
+    if not pr.get("merged", False):
+        return
+
+    repo = _repo_fullname(payload)
+    pr_number = pr.get("number", 0)
+    pr_title = pr.get("title", "")
+    pr_author = pr.get("user", {}).get("login", "unknown")
+    # merged_by 可能不在 payload 中，fallback 到 sender
+    merged_by = (
+        pr.get("merged_by", {}).get("login", "")
+        or payload.get("sender", {}).get("login", "unknown")
+    )
+
+    text = render_template("review_merged", {
+        "repo": repo,
+        "pr_number": str(pr_number),
+        "pr_title": pr_title,
+        "pr_author": pr_author,
+        "merged_by": merged_by,
+    })
+
+    title = f"PR 已合并: {pr_title} ({repo}#{pr_number})"
+    _send_mail(pr_author, title, text)
+
+
 async def _handle_issues(payload: Dict[str, Any]) -> None:
     """处理 issues 事件：assigned → 通知被指派人；opened+部署失败 → 通知运维。"""
     action = payload.get("action", "")
diff --git a/src/daemon/toolchain_templates.py b/src/daemon/toolchain_templates.py
index 4e3a067..c5d55f5 100644
--- a/src/daemon/toolchain_templates.py
+++ b/src/daemon/toolchain_templates.py
@@ -23,6 +23,7 @@ _TEMPLATE_MAP: Dict[str, str] = {
     "deploy_failure": "deploy_failure.md",
     "review_updated": "review_updated.md",
     "review_comment": "review_comment.md",
+    "review_merged": "review_merged.md",
 }
 
 # 模板缓存
diff --git a/templates/toolchain/review_merged.md b/templates/toolchain/review_merged.md
new file mode 100644
index 0000000..e76b685
--- /dev/null
+++ b/templates/toolchain/review_merged.md
@@ -0,0 +1,8 @@
+## PR 已合并 ✅
+
+**仓库**: {{repo}}
+**PR #{{pr_number}}**: {{pr_title}}
+**作者**: @{{pr_author}}
+**合并者**: @{{merged_by}}
+
+PR 已成功合并到主分支。