diff --git a/app/Http/Controllers/Admin/DashboardController.php b/app/Http/Controllers/Admin/DashboardController.php
index 905e9cd..0306f45 100644
--- a/app/Http/Controllers/Admin/DashboardController.php
+++ b/app/Http/Controllers/Admin/DashboardController.php
@@ -13,18 +13,37 @@ namespace App\Http\Controllers\Admin;
 use App\Http\Controllers\Controller;
 use App\Models\Room;
 use App\Models\User;
+use App\Services\ChatStateService;
 use Illuminate\View\View;
 
+/**
+ * 类功能：负责后台首页仪表盘的汇总统计展示。
+ */
 class DashboardController extends Controller
 {
+    /**
+     * 注入聊天室状态服务，供仪表盘读取实时在线数据。
+     */
+    public function __construct(
+        private readonly ChatStateService $chatState,
+    ) {}
+
     /**
      * 显示后台首页与全局统计
      */
     public function index(): View
     {
+        $onlineUsernames = collect();
+
+        foreach ($this->chatState->getAllActiveRoomIds() as $roomId) {
+            // 使用在线名单服务的懒清理结果，保证统计口径与聊天室在线列表一致。
+            $onlineUsernames = $onlineUsernames->merge(array_keys($this->chatState->getRoomUsers($roomId)));
+        }
+
         $stats = [
             'total_users' => User::count(),
             'total_rooms' => Room::count(),
+            'online_users' => $onlineUsernames->unique()->count(),
             // 更多统计指标以后再发掘
         ];
 
diff --git a/resources/views/admin/dashboard.blade.php b/resources/views/admin/dashboard.blade.php
index 0be6e0c..e516af0 100644
--- a/resources/views/admin/dashboard.blade.php
+++ b/resources/views/admin/dashboard.blade.php
@@ -13,6 +13,12 @@
             <h3 class="text-gray-500 text-sm font-medium mb-1">总计聊天频道数</h3>
             <p class="text-3xl font-bold text-gray-800">{{ $stats['total_rooms'] }}</p>
         </div>
+
+        <div class="bg-white rounded-xl shadow-sm p-6 border border-gray-100">
+            <h3 class="text-gray-500 text-sm font-medium mb-1">当前在线人数</h3>
+            <p class="text-3xl font-bold text-emerald-600">{{ $stats['online_users'] }}</p>
+            <p class="mt-2 text-xs text-gray-400">按 Redis 在线心跳实时去重统计</p>
+        </div>
     </div>
 
     <div class="bg-white rounded-xl shadow-sm border border-gray-100 overflow-hidden">
diff --git a/tests/Feature/Feature/AdminDashboardControllerTest.php b/tests/Feature/Feature/AdminDashboardControllerTest.php
new file mode 100644
index 0000000..c42b0dd
--- /dev/null
+++ b/tests/Feature/Feature/AdminDashboardControllerTest.php
@@ -0,0 +1,65 @@
+<?php
+
+/**
+ * 文件功能：后台仪表盘统计功能测试
+ *
+ * 覆盖后台首页在线人数卡片展示，确保仪表盘统计口径与聊天室在线名单一致。
+ *
+ * @author   ChatRoom Laravel
+ *
+ * @version  1.0.0
+ */
+
+namespace Tests\Feature\Feature;
+
+use App\Models\Room;
+use App\Models\User;
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Illuminate\Support\Facades\Redis;
+use Tests\TestCase;
+
+/**
+ * 类功能：验证后台仪表盘核心统计数据的展示。
+ */
+class AdminDashboardControllerTest extends TestCase
+{
+    use RefreshDatabase;
+
+    /**
+     * 每个测试前清空 Redis，避免在线名单缓存影响断言结果。
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        Redis::flushall();
+    }
+
+    /**
+     * 验证后台仪表盘会显示去重后的在线人数。
+     */
+    public function test_dashboard_displays_unique_online_user_count(): void
+    {
+        $siteOwner = User::factory()->create([
+            'id' => 1,
+            'username' => 'site-owner',
+        ]);
+
+        $roomOne = Room::create(['room_name' => '后台房间一']);
+        $roomTwo = Room::create(['room_name' => '后台房间二']);
+
+        // 同一用户重复出现在多个房间时，仪表盘应按全局去重后的在线人数展示。
+        Redis::hset("room:{$roomOne->id}:users", 'alice', json_encode(['username' => 'alice'], JSON_UNESCAPED_UNICODE));
+        Redis::setex("room:{$roomOne->id}:alive:alice", 90, 1);
+        Redis::hset("room:{$roomTwo->id}:users", 'alice', json_encode(['username' => 'alice'], JSON_UNESCAPED_UNICODE));
+        Redis::setex("room:{$roomTwo->id}:alive:alice", 90, 1);
+        Redis::hset("room:{$roomTwo->id}:users", 'bob', json_encode(['username' => 'bob'], JSON_UNESCAPED_UNICODE));
+        Redis::setex("room:{$roomTwo->id}:alive:bob", 90, 1);
+
+        $response = $this->actingAs($siteOwner)->get(route('admin.dashboard'));
+
+        $response->assertOk();
+        $response->assertSee('当前在线人数');
+        $response->assertSee('2');
+    }
+}