diff --git a/frontend/src/router/AppErrorBoundary.tsx b/frontend/src/router/AppErrorBoundary.tsx
new file mode 100644
index 0000000..24c6da9
--- /dev/null
+++ b/frontend/src/router/AppErrorBoundary.tsx
@@ -0,0 +1,49 @@
+// REQ-USR-003: 路由级 ErrorBoundary（子路由渲染抛错兜底 + 返回主页入口，spec § 3 error / D7）。
+import { Component, type ErrorInfo, type ReactNode } from 'react';
+import { Button, Result } from 'antd';
+
+interface AppErrorBoundaryProps {
+  children: ReactNode;
+}
+
+interface AppErrorBoundaryState {
+  hasError: boolean;
+}
+
+export default class AppErrorBoundary extends Component<
+  AppErrorBoundaryProps,
+  AppErrorBoundaryState
+> {
+  state: AppErrorBoundaryState = { hasError: false };
+
+  static getDerivedStateFromError(): AppErrorBoundaryState {
+    return { hasError: true };
+  }
+
+  componentDidCatch(_error: Error, _info: ErrorInfo): void {
+    // 兜底：捕获即进入降级 UI；此处可接入日志上报（MVP 不上报）。
+  }
+
+  private handleGoHome = () => {
+    this.setState({ hasError: false });
+    // 直接回主页（不依赖 hooks，class 组件用 location）
+    window.location.assign('/');
+  };
+
+  render() {
+    if (this.state.hasError) {
+      return (
+        <Result
+          status="error"
+          title="页面出错，请刷新或返回主页"
+          extra={
+            <Button type="primary" onClick={this.handleGoHome}>
+              返回主页
+            </Button>
+          }
+        />
+      );
+    }
+    return this.props.children;
+  }
+}
diff --git a/frontend/src/router/index.tsx b/frontend/src/router/index.tsx
index 5dc09a7..9510baf 100644
--- a/frontend/src/router/index.tsx
+++ b/frontend/src/router/index.tsx
@@ -1,18 +1,54 @@
-// REQ-USR-004: 路由表（FE 共享骨架）。/login → LoginPage；'/' 占位待 FE-02 落地。
+// REQ-USR-003 / REQ-USR-004: 路由表（FE 共享骨架）。
+// FE-02 将 '/' 占位替换为应用外壳 + 受保护嵌套路由 + 错误边界。
+// 子路由目标内容（FE-03 用户列表 / FE-04 用户单据）由后续 FE 落地，本处仅留可挂载占位。
 import { Routes, Route, Navigate } from 'react-router-dom';
 import LoginPage from '../pages/usr/Login/LoginPage';
+import RequireAuth from './RequireAuth';
+import RedirectIfAuthed from './RedirectIfAuthed';
+import AppErrorBoundary from './AppErrorBoundary';
+import AppLayout from '../layouts/AppLayout/AppLayout';
+import HomePage from '../pages/home/HomePage/HomePage';
 
-// 主页占位：FE-02 将替换为真实应用壳。本 REQ 仅需 '/' 可达（登录成功 navigate('/')）。
-function HomePlaceholder() {
-  return <div id="home-placeholder" />;
+// FE-03 用户列表容器占位（本 FE 仅提供导航入口与标签挂载位）
+function UserListPlaceholder() {
+  return <div data-testid="fe03-userlist-placeholder" />;
+}
+
+// FE-04 用户单据容器占位（新增 / 修改）
+function UserDetailPlaceholder() {
+  return <div data-testid="fe04-userdetail-placeholder" />;
 }
 
 export default function AppRouter() {
   return (
     <Routes>
-      <Route path="/login" element={<LoginPage />} />
-      <Route path="/" element={<HomePlaceholder />} />
-      <Route path="*" element={<Navigate to="/login" replace />} />
+      {/* 登录页：放行，包 RedirectIfAuthed（已登录回主页，BR2），不包 AppLayout */}
+      <Route
+        path="/login"
+        element={
+          <RedirectIfAuthed>
+            <LoginPage />
+          </RedirectIfAuthed>
+        }
+      />
+
+      {/* 受保护区：RequireAuth > AppLayout（外壳），外壳内套 ErrorBoundary 兜底子路由抛错 */}
+      <Route element={<RequireAuth />}>
+        <Route
+          element={
+            <AppErrorBoundary>
+              <AppLayout />
+            </AppErrorBoundary>
+          }
+        >
+          <Route index element={<HomePage />} />
+          <Route path="/usr/users" element={<UserListPlaceholder />} />
+          <Route path="/usr/users/new" element={<UserDetailPlaceholder />} />
+          <Route path="/usr/users/:id" element={<UserDetailPlaceholder />} />
+          {/* 受保护区内未匹配 → 回主页（D7） */}
+          <Route path="*" element={<Navigate to="/" replace />} />
+        </Route>
+      </Route>
     </Routes>
   );
 }
diff --git a/frontend/tests/unit/AppErrorBoundary.test.tsx b/frontend/tests/unit/AppErrorBoundary.test.tsx
new file mode 100644
index 0000000..b1f626c
--- /dev/null
+++ b/frontend/tests/unit/AppErrorBoundary.test.tsx
@@ -0,0 +1,32 @@
+// REQ-USR-003: 路由级 ErrorBoundary 子组件抛错兜底（spec § 3 error / D7）
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { MemoryRouter } from 'react-router-dom';
+import AppErrorBoundary from '../../src/router/AppErrorBoundary';
+
+function Boom(): React.ReactElement {
+  throw new Error('boom');
+}
+
+describe('AppErrorBoundary', () => {
+  // 抑制 React 在 ErrorBoundary 测试时打印的 error 噪声
+  let spy: ReturnType<typeof vi.spyOn>;
+  beforeEach(() => {
+    spy = vi.spyOn(console, 'error').mockImplementation(() => {});
+  });
+  afterEach(() => {
+    spy.mockRestore();
+  });
+
+  it('renders fallback with 返回主页 when child throws', () => {
+    render(
+      <MemoryRouter>
+        <AppErrorBoundary>
+          <Boom />
+        </AppErrorBoundary>
+      </MemoryRouter>,
+    );
+    expect(screen.getByText('页面出错，请刷新或返回主页')).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: '返回主页' })).toBeInTheDocument();
+  });
+});
diff --git a/frontend/tests/unit/router.test.tsx b/frontend/tests/unit/router.test.tsx
new file mode 100644
index 0000000..f509540
--- /dev/null
+++ b/frontend/tests/unit/router.test.tsx
@@ -0,0 +1,43 @@
+// REQ-USR-003: 路由表接线（替换 / 占位，含守卫与重定向，BR1/BR2/D7）
+import { describe, it, expect } from 'vitest';
+import { screen } from '@testing-library/react';
+import { renderShell } from './renderShell';
+import AppRouter from '../../src/router';
+import type { AuthUser } from '../../src/api/types';
+
+const ADMIN: AuthUser = { id: 1, sUserName: '朱子纯', sUserType: '超级管理员', sLanguage: '中文' };
+
+function renderRouter(initialEntries: string[], preloadedAuth?: Parameters<typeof renderShell>[1]['preloadedAuth']) {
+  return renderShell(<AppRouter />, { initialEntries, preloadedAuth });
+}
+
+describe('AppRouter', () => {
+  it('unauthenticated / redirects to /login', () => {
+    renderRouter(['/'], { token: null, user: null });
+    // 登录页含「用户登录」标题
+    expect(screen.getByText('用户登录')).toBeInTheDocument();
+  });
+
+  it('authenticated / renders HomePage shell', () => {
+    renderRouter(['/'], { token: 't', user: ADMIN });
+    expect(screen.getByText('KPI监控')).toBeInTheDocument();
+    expect(screen.getByRole('button', { name: '全部导航' })).toBeInTheDocument();
+  });
+
+  it('authenticated /usr/users renders under AppLayout', () => {
+    renderRouter(['/usr/users'], { token: 't', user: ADMIN });
+    // 外壳顶栏在；用户列表标签激活（占位内容由 FE-03 落地）
+    expect(screen.getByRole('button', { name: '全部导航' })).toBeInTheDocument();
+    expect(screen.getByTestId('tab-userlist').getAttribute('aria-pressed')).toBe('true');
+  });
+
+  it('authenticated /login redirects to /', () => {
+    renderRouter(['/login'], { token: 't', user: ADMIN });
+    expect(screen.getByText('KPI监控')).toBeInTheDocument();
+  });
+
+  it('unknown protected path redirects to /', () => {
+    renderRouter(['/no/such/path'], { token: 't', user: ADMIN });
+    expect(screen.getByText('KPI监控')).toBeInTheDocument();
+  });
+});