diff --git a/backend/app/modules/admin/api/announcement.py b/backend/app/modules/admin/api/announcement.py
index f65cf13a..46b26136 100644
--- a/backend/app/modules/admin/api/announcement.py
+++ b/backend/app/modules/admin/api/announcement.py
@@ -7,7 +7,7 @@
   - `frontend_router`（prefix=/announcements，在 app/__init__.py 以 /api/announcements 挂载）
 
 鉴权：
-  - 后台：require_permission("frontend:admin:announcement:manage")
+  - 后台：require_permission(PERM_ANNOUNCEMENT)，码定义在 permission_service
   - 前台：仅要求登录（App 全量在 AuthGuard 内，无匿名场景）
 
 Status 用字符串列（draft/published/offline），见 app/models/announcement.py。
@@ -27,13 +27,16 @@
 from app.models.announcement import Announcement, AnnouncementStatus
 from app.modules.admin.api.auth import require_permission
 from app.services.identity_service import IdentityService
+from app.services.permission_service import PERM_ANNOUNCEMENT
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/announcements", tags=["admin-announcements"])
 frontend_router = APIRouter(prefix="/announcements", tags=["announcements"])
 
-PERM_CODE = "frontend:admin:announcement:manage"
+# 与 permission_service 的派生表共用同一个常量：全局角色「超级管理员」默认拿到它，
+# 其他角色可在权限管理里勾选。两处若各写一份字符串，迟早漂移。
+PERM_CODE = PERM_ANNOUNCEMENT
 
 VALID_STATUS = (
     AnnouncementStatus.DRAFT,
@@ -50,7 +53,13 @@
 
 
 def ensure_announcement_permission() -> None:
-    """确保权限码已注册到 permissions 表（幂等，已存在自动跳过）。"""
+    """确保权限码已注册到 permissions 表（幂等，已存在自动跳过）。
+
+    只在「权限管理」列表的注册块（permissions.get_all_permissions）里调用：
+    该码要在权限管理页可勾选，就必须在**读到权限列表时**先落库。切勿在下面各接口
+    函数体内调用——require_permission 是 FastAPI 依赖，先于函数体执行，没权限的
+    账号会先被 403 挡住，永远走不到注册那行（生产上就是这样自锁的）。
+    """
     IdentityService.add_permission(
         permission_id="perm_frontend_admin_announcement_manage",
         code=PERM_CODE,
@@ -153,7 +162,6 @@ async def admin_list_announcements(
     db: AsyncSession = Depends(get_db),
     _: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     conds = []
     if status:
         conds.append(Announcement.status == _validate_status(status))
@@ -180,7 +188,6 @@ async def create_announcement(
     db: AsyncSession = Depends(get_db),
     current_user: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     st = _validate_status(payload.status)
     ann = Announcement(
         title=payload.title.strip(),
@@ -203,7 +210,6 @@ async def update_announcement(
     db: AsyncSession = Depends(get_db),
     _: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     ann = await _get_or_404(db, aid)
 
     if payload.title is not None:
@@ -229,7 +235,6 @@ async def publish_announcement(
     db: AsyncSession = Depends(get_db),
     _: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     ann = await _get_or_404(db, aid)
     ann.status = AnnouncementStatus.PUBLISHED
     if ann.published_at is None:
@@ -245,7 +250,6 @@ async def offline_announcement(
     db: AsyncSession = Depends(get_db),
     _: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     ann = await _get_or_404(db, aid)
     ann.status = AnnouncementStatus.OFFLINE
     await db.commit()
@@ -259,7 +263,6 @@ async def delete_announcement(
     db: AsyncSession = Depends(get_db),
     _: Dict[str, Any] = require_permission(PERM_CODE),
 ):
-    ensure_announcement_permission()
     ann = await _get_or_404(db, aid)
     await db.delete(ann)
     await db.commit()
diff --git a/backend/app/modules/admin/api/permissions.py b/backend/app/modules/admin/api/permissions.py
index 360c0db3..fe1f25e4 100644
--- a/backend/app/modules/admin/api/permissions.py
+++ b/backend/app/modules/admin/api/permissions.py
@@ -59,6 +59,10 @@ async def get_all_permissions(
         ensure_task_policy_permission()
         from app.modules.admin.services.knowledge_permissions import ensure_knowledge_contribution_permission
         ensure_knowledge_contribution_permission()
+        # 公告管理：码在 permissions 表里存在才能在权限管理页勾给非超管角色。
+        # 必须放在这里（读权限列表时），不能放接口函数体内，否则 403 会先挡住注册。
+        from app.modules.admin.api.announcement import ensure_announcement_permission
+        ensure_announcement_permission()
         permissions = db_manager.get_all_permissions()
         return DataResponse(
             code=0,
diff --git a/backend/app/services/permission_service.py b/backend/app/services/permission_service.py
index e9ffb314..6932e42c 100644
--- a/backend/app/services/permission_service.py
+++ b/backend/app/services/permission_service.py
@@ -24,11 +24,21 @@
 PERM_PROJECT_LEDGER_IMPORT = "frontend:admin:project-ledger-import:show"
 PERM_KNOWLEDGE_CONTRIBUTION = "frontend:admin:knowledge:show"
 
+# 后台「公告管理」（活动中心公告的发布 / 下线 / 置顶）的可见/可调判据。
+# 公告是运营动作，默认只开给全局角色「超级管理员」（admin 账号照旧直通）；
+# 其他角色要在权限管理里显式勾选——该码由 announcement.ensure_announcement_permission
+# 在 permissions 的注册块里写入，不会在接口函数体内写（见该函数 docstring）。
+PERM_ANNOUNCEMENT = "frontend:admin:announcement:manage"
+
 # 「拥有哪个全局角色 → 额外获得哪些权限码」。开发者 / 超级管理员可编辑详情模板；
-# 一键导入全部项目只开给超级管理员（admin 账号照旧直通）。
+# 一键导入全部项目、公告管理只开给超级管理员（admin 账号照旧直通）。
 _GLOBAL_ROLE_DERIVED_PERMISSIONS: Dict[str, tuple] = {
     "开发者": (PERM_PROJECT_INFO_TEMPLATE,),
-    "超级管理员": (PERM_PROJECT_INFO_TEMPLATE, PERM_PROJECT_LEDGER_IMPORT),
+    "超级管理员": (
+        PERM_PROJECT_INFO_TEMPLATE,
+        PERM_PROJECT_LEDGER_IMPORT,
+        PERM_ANNOUNCEMENT,
+    ),
 }
 _user_roles_cache: Dict[str, Dict[str, Any]] = {}
 _user_roles_cache_ts: Dict[str, float] = {}
diff --git a/backend/tests/test_announcement_api.py b/backend/tests/test_announcement_api.py
index a158d5f4..047bfa69 100644
--- a/backend/tests/test_announcement_api.py
+++ b/backend/tests/test_announcement_api.py
@@ -12,7 +12,8 @@
     - POST       /api/admin/announcements/{id}/publish | /offline
 
 一律不连真库：conftest 已把 app.core.database 换成 MagicMock；这里 override
-get_db 返回可编排的 Mock，并打桩 permissions 表写入（ensure_announcement_permission）。
+get_db 返回可编排的 Mock。权限码注册只应发生在 permissions.get_all_permissions
+的注册块里——接口路径里写 permissions 表会直接让本文件用例失败（回归钉）。
 """
 from datetime import datetime
 from types import SimpleNamespace
@@ -71,9 +72,19 @@ def _ann(**over):
 
 
 @pytest.fixture(autouse=True)
-def _stub_permission_write(monkeypatch):
-    """ensure_announcement_permission 会写 permissions 表，单测里打桩。"""
-    monkeypatch.setattr(IdentityService, "add_permission", lambda *a, **kw: True)
+def _forbid_inline_permission_write(monkeypatch):
+    """回归钉：接口路径不允许写 permissions 表。
+
+    原实现把 ensure_announcement_permission() 放在各后台接口函数体首行，而
+    require_permission 是依赖、先于函数体执行 → 没有该权限的账号永远 403，
+    注册那行永远走不到（生产自锁）。这里把它设成硬失败，防止有人再加回去。
+    """
+    def _boom(*args, **kwargs):
+        raise AssertionError(
+            "接口路径不应注册权限码（应在 permissions.get_all_permissions 的注册块里）"
+        )
+
+    monkeypatch.setattr(IdentityService, "add_permission", _boom)
 
 
 @pytest.fixture
@@ -234,3 +245,49 @@ def test_delete_returns_id(make_client, db):
 
     assert body == {"ok": True, "id": 1}
     db.delete.assert_awaited_once()
+
+
+def test_admin_api_allowed_with_derived_permission(make_client, db):
+    """超管不是靠 admin 账号直通，而是登录态 permissions 里带了这个码。"""
+    db.execute = AsyncMock(side_effect=[_Res(scalar=0), _Res(rows=[])])
+    super_admin = {
+        "id": "u-sa",
+        "username": "bob",
+        "permissions": [ann_api.PERM_CODE],
+        "roles": {},
+    }
+
+    response = make_client(super_admin).get("/api/admin/announcements")
+
+    assert response.status_code == 200
+
+
+# ---------------------------------------------------------------------------
+# 权限码注册：只能走 permissions 的注册块，且超管默认可见
+# ---------------------------------------------------------------------------
+
+def test_super_admin_role_derives_announcement_permission():
+    """全局角色「超级管理员」默认拿到公告管理码（否则后台入口对超管不可见）。"""
+    from app.services.permission_service import (
+        _GLOBAL_ROLE_DERIVED_PERMISSIONS,
+        PERM_ANNOUNCEMENT,
+    )
+
+    assert PERM_ANNOUNCEMENT == ann_api.PERM_CODE
+    assert PERM_ANNOUNCEMENT in _GLOBAL_ROLE_DERIVED_PERMISSIONS["超级管理员"]
+
+
+def test_ensure_registers_code_for_permission_management(monkeypatch):
+    """权限管理页要能勾到该码：注册时写入的 code 必须与接口闸门一致。"""
+    captured = {}
+
+    def _capture(**kwargs):
+        captured.update(kwargs)
+        return True
+
+    monkeypatch.setattr(IdentityService, "add_permission", _capture)
+
+    ann_api.ensure_announcement_permission()
+
+    assert captured["code"] == ann_api.PERM_CODE
+    assert captured["permission_id"] == "perm_frontend_admin_announcement_manage"