diff --git a/src/api/mail_routes.py b/src/api/mail_routes.py
index b49ab29..ef83690 100644
--- a/src/api/mail_routes.py
+++ b/src/api/mail_routes.py
@@ -297,6 +297,25 @@ async def send_mail(body: Dict[str, Any]):
     return result
 
 
+@router.delete("")
+async def delete_mail(prefix: Optional[str] = Query(None)):
+    """批量删除邮件（按标题前缀匹配，status→cancelled）"""
+    if not prefix:
+        raise HTTPException(400, "`prefix` 查询参数必填")
+
+    bb = _bb()
+    tasks = bb.list_tasks()
+
+    deleted_ids = []
+    for t in tasks:
+        if t.title and t.title.startswith(prefix):
+            if t.status not in ("cancelled",):
+                bb.update_task_status(t.id, "cancelled", agent="mail-cleanup-api")
+                deleted_ids.append(t.id)
+
+    return {"ok": True, "deleted_count": len(deleted_ids), "deleted_ids": deleted_ids}
+
+
 @router.patch("/{mail_id}")
 async def update_mail(mail_id: str, body: Dict[str, Any]):
     """更新 Mail（标记已读/已执行）"""