diff --git a/core/auth/fba_jwt.py b/core/auth/fba_jwt.py
new file mode 100644
index 0000000..6a52e33
--- /dev/null
+++ b/core/auth/fba_jwt.py
@@ -0,0 +1,170 @@
+# -*- coding: utf-8 -*-
+"""FBA JWT 校验（Epic #159 · Phase 4）—— iAOP 业务接口接入 FBA 统一认证。
+
+背景：认证/RBAC 基座已迁移到 FBA（fastapi-best-architecture）。
+FBA access token 为 HS256 JWT，claims：{sub: 用户ID, session_uuid, exp}。
+iAOP 后端为零依赖标准库实现，本模块用 hmac/hashlib 手写 HS256 校验，
+不引入 PyJWT。
+
+用法（任意 iAOP HTTP 服务内）：
+
+    from core.auth.fba_jwt import FbaAuth, FbaAuthError
+
+    fba = FbaAuth.from_env()            # 读 FBA_TOKEN_SECRET_KEY / FBA_API_BASE
+    if fba is not None:                 # 未配置 → 调用方走旧 core/auth 会话
+        claims = fba.verify(authorization_header)   # 无效抛 FbaAuthError(401)
+        fba.require_perm(authorization_header, "iaop:admin")  # 无权抛 403
+
+权限码（按钮级）：
+    前端菜单播种时已写入 perms=iaop:<module>（deploy/fba/seed_iaop_menus.py）。
+    require_perm() 携用户 token 回源 FBA GET /auth/codes 校验（带 TTL 缓存，
+    避免每请求打满 FBA）。超管在 FBA 侧自动拥有全部权限码。
+
+双轨过渡：FBA_TOKEN_SECRET_KEY 未配置时 from_env() 返回 None，
+业务接口应继续接受旧 core/auth HMAC 会话（见 auth_api.require_auth），
+待 Phase 5 收尾时再移除旧轨。
+"""
+from __future__ import annotations
+
+import base64
+import hashlib
+import hmac
+import json
+import os
+import time
+import urllib.request
+import urllib.error
+from http import HTTPStatus
+from typing import Optional
+
+
+class FbaAuthError(Exception):
+    """FBA 认证/授权失败。status: 401 未认证，403 无权限，503 FBA 不可达。"""
+
+    def __init__(self, status: int, message: str) -> None:
+        super().__init__(message)
+        self.status = status
+        self.message = message
+
+
+def _b64url_decode(seg: str) -> bytes:
+    pad = "=" * (-len(seg) % 4)
+    return base64.urlsafe_b64decode(seg + pad)
+
+
+def _b64url_encode(raw: bytes) -> str:
+    return base64.urlsafe_b64encode(raw).rstrip(b"=").decode()
+
+
+class FbaAuth:
+    """FBA JWT 校验器（HS256，与 FBA backend/common/security/jwt.py 对齐）。"""
+
+    def __init__(self, secret_key: str, api_base: str = "http://127.0.0.1:8001/api/v1",
+                 perm_cache_ttl: int = 300) -> None:
+        if not secret_key:
+            raise ValueError("secret_key 不能为空")
+        self._secret = secret_key.encode()
+        self.api_base = api_base.rstrip("/")
+        self.perm_cache_ttl = perm_cache_ttl
+        # token → (expires_at, codes set)；简单内存缓存，进程级
+        self._perm_cache: dict[str, tuple[float, set]] = {}
+
+    @classmethod
+    def from_env(cls) -> Optional["FbaAuth"]:
+        """读环境变量构造；未配置 FBA_TOKEN_SECRET_KEY 时返回 None（降级旧轨）。"""
+        secret = os.environ.get("FBA_TOKEN_SECRET_KEY", "").strip()
+        if not secret:
+            return None
+        return cls(secret, os.environ.get(
+            "FBA_API_BASE", "http://127.0.0.1:8001/api/v1"))
+
+    # ------------------------------------------------------------------ JWT
+    def verify(self, authorization: str) -> dict:
+        """校验 'Bearer <token>'，返回 claims；失败抛 FbaAuthError(401)。"""
+        token = self._extract_bearer(authorization)
+        parts = token.split(".")
+        if len(parts) != 3:
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 格式无效")
+        signing_input = (parts[0] + "." + parts[1]).encode()
+        expect = _b64url_encode(hmac.new(self._secret, signing_input,
+                                         hashlib.sha256).digest())
+        if not hmac.compare_digest(expect, parts[2]):
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 签名无效")
+        try:
+            header = json.loads(_b64url_decode(parts[0]))
+            payload = json.loads(_b64url_decode(parts[1]))
+        except (ValueError, UnicodeDecodeError):
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 解析失败")
+        if header.get("alg") != "HS256":
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 算法不受支持")
+        if not payload.get("sub") or not payload.get("session_uuid"):
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 缺少必要字段")
+        exp = payload.get("exp")
+        if not isinstance(exp, (int, float)) or exp < time.time():
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 已过期")
+        return payload
+
+    @staticmethod
+    def _extract_bearer(authorization: str) -> str:
+        if not authorization:
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "未携带认证信息")
+        parts = authorization.split(None, 1)
+        if len(parts) != 2 or parts[0].lower() != "bearer":
+            raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "认证头格式应为 Bearer <token>")
+        return parts[1].strip()
+
+    # ------------------------------------------------------------- 权限码
+    def get_codes(self, authorization: str) -> set:
+        """携 token 回源 FBA /auth/codes 取权限码集合（带 TTL 缓存）。"""
+        token = self._extract_bearer(authorization)
+        now = time.time()
+        hit = self._perm_cache.get(token)
+        if hit and hit[0] > now:
+            return hit[1]
+        req = urllib.request.Request(
+            self.api_base + "/auth/codes",
+            headers={"Authorization": f"Bearer {token}"})
+        try:
+            with urllib.request.urlopen(req, timeout=5) as r:
+                d = json.loads(r.read().decode())
+        except urllib.error.HTTPError as e:
+            if e.code in (401, 403):
+                raise FbaAuthError(HTTPStatus.UNAUTHORIZED, "Token 已失效")
+            raise FbaAuthError(HTTPStatus.SERVICE_UNAVAILABLE,
+                               f"FBA 权限码查询失败：HTTP {e.code}")
+        except OSError:
+            raise FbaAuthError(HTTPStatus.SERVICE_UNAVAILABLE, "FBA 服务不可达")
+        if d.get("code") != 200 or not isinstance(d.get("data"), list):
+            raise FbaAuthError(HTTPStatus.SERVICE_UNAVAILABLE, "FBA 权限码响应异常")
+        codes = set(d["data"])
+        self._perm_cache[token] = (now + self.perm_cache_ttl, codes)
+        # 简单清理过期缓存项
+        for k in [k for k, v in self._perm_cache.items() if v[0] <= now]:
+            self._perm_cache.pop(k, None)
+        return codes
+
+    def require_perm(self, authorization: str, perm: str) -> dict:
+        """校验 token + 权限码；返回 claims。401/403 抛 FbaAuthError。"""
+        claims = self.verify(authorization)
+        codes = self.get_codes(authorization)
+        if perm not in codes:
+            raise FbaAuthError(HTTPStatus.FORBIDDEN, f"缺少权限：{perm}")
+        return claims
+
+
+# ---------------------------------------------------------------------------
+# 自测试用：生成与 FBA 同构的 HS256 token（tests 使用）
+# ---------------------------------------------------------------------------
+def make_test_token(secret: str, user_id: int = 1,
+                    session_uuid: str = "test-session",
+                    exp_offset: int = 3600) -> str:
+    header = _b64url_encode(json.dumps(
+        {"alg": "HS256", "typ": "JWT"}, separators=(",", ":")).encode())
+    payload = _b64url_encode(json.dumps({
+        "sub": str(user_id), "session_uuid": session_uuid,
+        "exp": time.time() + exp_offset,
+    }, separators=(",", ":")).encode())
+    sig = _b64url_encode(hmac.new(secret.encode(),
+                                  f"{header}.{payload}".encode(),
+                                  hashlib.sha256).digest())
+    return f"{header}.{payload}.{sig}"
diff --git a/core/auth/tests/test_fba_jwt.py b/core/auth/tests/test_fba_jwt.py
new file mode 100644
index 0000000..8255dd0
--- /dev/null
+++ b/core/auth/tests/test_fba_jwt.py
@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+"""FBA JWT 校验模块单元测试（Epic #159 · Phase 4）。
+
+运行：python -m unittest core.auth.tests.test_fba_jwt -v
+"""
+from __future__ import annotations
+
+import os
+import unittest
+
+from core.auth.fba_jwt import FbaAuth, FbaAuthError, make_test_token
+
+SECRET = "unit-test-secret-key"
+
+
+class FbaJwtTest(unittest.TestCase):
+    def setUp(self):
+        self.auth = FbaAuth(SECRET)
+
+    def test_verify_ok(self):
+        token = make_test_token(SECRET, user_id=42, session_uuid="s-1")
+        claims = self.auth.verify(f"Bearer {token}")
+        self.assertEqual(claims["sub"], "42")
+        self.assertEqual(claims["session_uuid"], "s-1")
+
+    def test_verify_expired(self):
+        token = make_test_token(SECRET, exp_offset=-10)
+        with self.assertRaises(FbaAuthError) as ctx:
+            self.auth.verify(f"Bearer {token}")
+        self.assertEqual(ctx.exception.status, 401)
+        self.assertIn("过期", ctx.exception.message)
+
+    def test_verify_bad_signature(self):
+        token = make_test_token("other-secret")
+        with self.assertRaises(FbaAuthError) as ctx:
+            self.auth.verify(f"Bearer {token}")
+        self.assertEqual(ctx.exception.status, 401)
+
+    def test_verify_missing_bearer(self):
+        for bad in ("", "token-abc", "Basic abc"):
+            with self.assertRaises(FbaAuthError) as ctx:
+                self.auth.verify(bad)
+            self.assertEqual(ctx.exception.status, 401)
+
+    def test_verify_malformed(self):
+        with self.assertRaises(FbaAuthError):
+            self.auth.verify("Bearer not-a-jwt")
+
+    def test_missing_fields(self):
+        # 无 session_uuid 的 token（签名正确但字段缺失）
+        import base64, hashlib, hmac, json, time
+        enc = lambda b: base64.urlsafe_b64encode(b).rstrip(b"=").decode()
+        header = enc(json.dumps({"alg": "HS256", "typ": "JWT"}).encode())
+        payload = enc(json.dumps({"sub": "1", "exp": time.time() + 60}).encode())
+        sig = enc(hmac.new(SECRET.encode(), f"{header}.{payload}".encode(),
+                           hashlib.sha256).digest())
+        with self.assertRaises(FbaAuthError) as ctx:
+            self.auth.verify(f"Bearer {header}.{payload}.{sig}")
+        self.assertIn("字段", ctx.exception.message)
+
+    def test_from_env_absent(self):
+        os.environ.pop("FBA_TOKEN_SECRET_KEY", None)
+        self.assertIsNone(FbaAuth.from_env())
+
+    def test_from_env_present(self):
+        os.environ["FBA_TOKEN_SECRET_KEY"] = SECRET
+        try:
+            auth = FbaAuth.from_env()
+            self.assertIsNotNone(auth)
+            token = make_test_token(SECRET)
+            self.assertEqual(auth.verify(f"Bearer {token}")["sub"], "1")
+        finally:
+            os.environ.pop("FBA_TOKEN_SECRET_KEY", None)
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/deploy/fba/README.md b/deploy/fba/README.md
index 8dea2a2..ae26f3c 100644
--- a/deploy/fba/README.md
+++ b/deploy/fba/README.md
@@ -86,9 +86,32 @@ docker exec -it fba_postgres psql -U postgres -d fba       # 进数据库
   脚本幂等：注册 iAOP 6 模块菜单（含子菜单）、创建 `engineer`/`viewer`
   角色并按 PRD 8.2 分配菜单。之后在 FBA 后台给用户分配角色即可。
   未播种时前端自动降级为本地角色过滤，菜单不会空白。
-- **Phase 3**：FBA UI（Vue3 + AntDV）构建时设置
-  `VITE_GLOB_API_URL=http://<域名>/fba`，产物由 nginx 挂在 `/fba-admin/`，
-  作为用户/角色/菜单管理界面。
+- **Phase 3**：FBA UI（Vue3 + AntDV）管理界面已预构建，产物在
+  `deploy/fba/artifacts/fba-ui-dist.tar.gz`（构建参数 `VITE_BASE=/fba-admin/`、
+  `VITE_GLOB_API_URL=http://39.101.182.167:8090/fba`）。部署：
+  ```bash
+  cd /opt/apps/iAOP
+  mkdir -p deploy/fba/fba-ui
+  tar -xzf deploy/fba/artifacts/fba-ui-dist.tar.gz -C deploy/fba/fba-ui/
+  # 确认 nginx 已 include 最新 nginx-fba.conf（含 /fba-admin/ 段）后 reload
+  nginx -t && nginx -s reload
+  ```
+  入口 `http://39.101.182.167:8090/fba-admin/`，用 FBA 账号登录即可管理
+  用户/角色/菜单/日志。iAOP 顶栏对 admin 角色提供「系统管理」直达链接。
+  若需重新构建（如换域名）：改 `fba-ui/apps/web-antdv-next/.env.production`
+  后 `pnpm --filter @vben/web-antdv-next build`（Vben5 monorepo，需 pnpm）。
+- **Phase 4**：业务接口按钮级权限。
+  - 前端：`IAOP_SESSION.perms()` / `hasPerm(code)` 读取 FBA `/auth/codes`
+    权限码（超管自动拥有全部；菜单播种时已写入 `iaop:<module>`）。
+  - 后端：`core/auth/fba_jwt.py` 提供零依赖 HS256 校验器 `FbaAuth`
+    （与 FBA 的 JWT 同构：claims = sub/session_uuid/exp，密钥取环境变量
+    `FBA_TOKEN_SECRET_KEY`，**必须与 fba.env 的 TOKEN_SECRET_KEY 一致**）。
+    业务服务内 `FbaAuth.from_env()` 返回 None 时走旧 core/auth 会话（双轨过渡）。
+    按钮级校验用 `fba.require_perm(authorization, "iaop:xxx")`（回源
+    `/auth/codes`，带 5 分钟内存缓存）。
+  - 单元测试：`python -m unittest core.auth.tests.test_fba_jwt -v`（8 例全过）。
+- **Phase 5**：收尾。待全部 Phase 部署验收后：旧 core/auth 登录轨与
+  UserStore 本地账号降级保留为演示模式；生产环境以 FBA 为唯一认证源。
 
 ## 注意事项
 
diff --git a/deploy/fba/artifacts/fba-ui-dist.tar.gz b/deploy/fba/artifacts/fba-ui-dist.tar.gz
new file mode 100644
index 0000000..bdfd730
Binary files /dev/null and b/deploy/fba/artifacts/fba-ui-dist.tar.gz differ
diff --git a/deploy/fba/nginx-fba.conf b/deploy/fba/nginx-fba.conf
index 085b6a6..89a3a69 100644
--- a/deploy/fba/nginx-fba.conf
+++ b/deploy/fba/nginx-fba.conf
@@ -34,3 +34,33 @@ location /fba/ {
 
     proxy_read_timeout 60s;
 }
+
+# =============================================================================
+# Phase 3：FBA UI 静态站点（用户/角色/菜单/日志管理界面）
+#
+# 部署：将 deploy/fba/artifacts/fba-ui-dist.tar.gz 解压到
+#       /opt/apps/iAOP/deploy/fba/fba-ui/（解压后应存在 fba-ui/dist/index.html）
+#       tar -xzf deploy/fba/artifacts/fba-ui-dist.tar.gz -C deploy/fba/fba-ui/
+#
+# 产物构建参数（已固化在包内）：
+#   VITE_BASE=/fba-admin/
+#   VITE_GLOB_API_URL=http://39.101.182.167:8090/fba
+# 入口：http://39.101.182.167:8090/fba-admin/
+# =============================================================================
+
+location /fba-admin/ {
+    alias /opt/apps/iAOP/deploy/fba/fba-ui/dist/;
+    index index.html;
+
+    # SPA 路由回退（hash 模式下 mostly 用不到，兜底）
+    try_files $uri $uri/ /fba-admin/index.html;
+
+    # 带 hash 的静态资源长缓存；index.html 不缓存
+    location ~* \.(js|css|png|jpg|jpeg|gif|svg|woff2?)$ {
+        expires 7d;
+        add_header Cache-Control "public";
+    }
+    location = /fba-admin/index.html {
+        add_header Cache-Control "no-cache";
+    }
+}
diff --git a/web/shared/pro-header.js b/web/shared/pro-header.js
index 92f75db..356d14d 100644
--- a/web/shared/pro-header.js
+++ b/web/shared/pro-header.js
@@ -311,6 +311,21 @@
       var color = IAOP_SESSION.ROLE_TAG_COLORS[u.role] || "default";
       var label = IAOP_SESSION.ROLE_LABELS[u.role] || u.role;
       userBox.appendChild(el("span", "pro-tag pro-tag-" + color, label));
+
+      // Epic #159 Phase 3：FBA 在线且当前为 admin → 顶栏提供「系统管理」
+      // 直达 FBA UI（用户/角色/菜单/日志管理），新标签打开
+      if (u.role === "admin" && IAOP_SESSION.fbaStatus) {
+        IAOP_SESSION.fbaStatus().then(function (st) {
+          if (!st.available) return;
+          var link = el("a", "pro-logout", "系统管理");
+          link.href = "/fba-admin/"; // nginx 绝对路径（deploy/fba/nginx-fba.conf）
+          link.target = "_blank";
+          link.rel = "noopener";
+          link.style.textDecoration = "none";
+          link.style.display = "inline-block";
+          right.insertBefore(link, logoutBtn);
+        });
+      }
       // 菜单异步：FBA token 存在时取服务端授权菜单树（Phase 2）
       IAOP_SESSION.menuTree(u).then(renderMenu);
     });
diff --git a/web/shared/session.js b/web/shared/session.js
index f042ef5..c8f8680 100644
--- a/web/shared/session.js
+++ b/web/shared/session.js
@@ -446,6 +446,27 @@ var IAOP_SESSION = (function () {
       .catch(function () { return modulesFor(user.role); });
   }
 
+  /* ---- Epic #159 Phase 4：按钮级权限码 ------------------------------------
+   * FBA GET /auth/codes 返回当前用户权限码集合（服务端按角色聚合；
+   * 超管返回全部菜单 perms，含播种脚本写入的 iaop:<module>）。
+   * 结果按会话缓存（登录后只拉一次），非 FBA 轨道返回空数组。 */
+  var _codesCache = null; // Promise<string[]> | null
+  function perms() {
+    if (_codesCache) return _codesCache;
+    if (!readFbaToken()) return Promise.resolve([]);
+    _codesCache = fbaFetch("/auth/codes")
+      .then(function (r) { return r.ok ? r.json() : null; })
+      .then(function (d) {
+        return d && d.code === 200 && Array.isArray(d.data) ? d.data : [];
+      })
+      .catch(function () { return []; });
+    return _codesCache;
+  }
+  function hasPerm(code) {
+    return perms().then(function (codes) {
+      return codes.indexOf(code) >= 0;
+    });
+  }
 
   return {
     MODULES: MODULES,
@@ -461,7 +482,9 @@ var IAOP_SESSION = (function () {
     fbaStatus: fbaStatus,
     getCaptcha: getCaptcha,
     getAuthHeaders: getAuthHeaders,
-    menuTree: menuTree
+    menuTree: menuTree,
+    perms: perms,
+    hasPerm: hasPerm
   };
 })();