diff --git a/SweetChatService/Handlers/WebSocketMessageHandler.cs b/SweetChatService/Handlers/WsMsgHandler.cs
similarity index 72%
rename from SweetChatService/Handlers/WebSocketMessageHandler.cs
rename to SweetChatService/Handlers/WsMsgHandler.cs
index 3dfe0f9..de95cad 100644
--- a/SweetChatService/Handlers/WebSocketMessageHandler.cs
+++ b/SweetChatService/Handlers/WsMsgHandler.cs
@@ -13,13 +13,13 @@ using System.Threading.Tasks;
 
 namespace SweetChatService.Handlers
 {
-    internal class WebSocketMessageHandler(ILogger<WebSocketMessageHandler> logger,
-        WebSocketSessionManager sessionManager,
-        UserService userService)
+    internal class WsMsgHandler(ILogger<WsMsgHandler> logger,
+        WsSessionManager sessionManager,
+        PrivateChatService privateChatService)
     {
-        private readonly ILogger<WebSocketMessageHandler> _logger = logger;
-        private readonly WebSocketSessionManager _sessionManager = sessionManager;
-        private readonly UserService _userService = userService;
+        private readonly ILogger<WsMsgHandler> _logger = logger;
+        private readonly WsSessionManager _sessionManager = sessionManager;
+        private readonly PrivateChatService _privateChatService = privateChatService;
 
         public async ValueTask HandleAsync(WebSocketSession session, WebSocketPackage package)
         {
@@ -55,20 +55,17 @@ namespace SweetChatService.Handlers
         {
             switch (msg.Type)
             {
-                case ImMessageType.CHAT:
-                    if (_sessionManager.TryGet(msg.To, out var toSession))
-                    {
-                        await toSession.SendAsync(msg.Content);
-                    }
+                case ImMessageType.CHAT_PRIVATE:
+                    await _privateChatService.HandleAsync(msg);
                     break;
 
                 case ImMessageType.ONLINE:
                     _sessionManager.Add(msg.From, session);
-                    await session.SendAsync("ok");
+                    await session.SendAsync(ImMessage.SystemMessage(msg.From, "OK").ToJson());
                     break;
 
                 case ImMessageType.HEARTBEAT:
-                    await session.SendAsync("ok");
+                    await session.SendAsync(ImMessage.SystemMessage(msg.From, "OK").ToJson());
                     break;
             }
         }
diff --git a/SweetChatService/Handlers/WebSocketSessionManager.cs b/SweetChatService/Handlers/WsSessionManager.cs
similarity index 63%
rename from SweetChatService/Handlers/WebSocketSessionManager.cs
rename to SweetChatService/Handlers/WsSessionManager.cs
index 07e03e0..633a74f 100644
--- a/SweetChatService/Handlers/WebSocketSessionManager.cs
+++ b/SweetChatService/Handlers/WsSessionManager.cs
@@ -3,7 +3,7 @@ using System.Collections.Concurrent;
 
 namespace SweetChatService.Handlers
 {
-    internal class WebSocketSessionManager
+    internal class WsSessionManager
     {
         private readonly ConcurrentDictionary<string, WebSocketSession> _sessions = new();
 
@@ -17,6 +17,19 @@ namespace SweetChatService.Handlers
             _sessions.TryRemove(userId, out _);
         }
 
+        public void RemoveBySession(string sessionId)
+        {
+            var keys = _sessions
+                .Where(x => ReferenceEquals(x.Value.SessionID, sessionId))
+                .Select(x => x.Key)
+                .ToList();
+
+            foreach (var key in keys)
+            {
+                _sessions.TryRemove(key, out _);
+            }
+        }
+
         public bool TryGet(string userId, out WebSocketSession? session)
         {
             return _sessions.TryGetValue(userId, out session);
diff --git a/SweetChatService/Models/ImMessage.cs b/SweetChatService/Models/ImMessage.cs
index ec334cc..4c3814c 100644
--- a/SweetChatService/Models/ImMessage.cs
+++ b/SweetChatService/Models/ImMessage.cs
@@ -1,4 +1,5 @@
-using System.Text.Json.Serialization;
+using System.Text.Json;
+using System.Text.Json.Serialization;
 
 namespace SweetChatService.Models
 {
@@ -15,5 +16,28 @@ namespace SweetChatService.Models
 
         [JsonPropertyName("content")]
         public string Content { get; set; } = default!;
+
+        public static ImMessage SystemMessage(string to, string content)
+        {
+            return new ImMessage
+            {
+                Type = ImMessageType.SYSTEM,
+                From = "SYSTEM",
+                To = to,
+                Content = content
+            };
+        }
+
+        /// <summary>
+        /// 转为 JSON 字符串
+        /// </summary>
+        public string ToJson()
+        {
+            return JsonSerializer.Serialize(this, new JsonSerializerOptions
+            {
+                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+                DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+            });
+        }
     }
 }
diff --git a/SweetChatService/Models/ImMessageType.cs b/SweetChatService/Models/ImMessageType.cs
index 4d8b959..c4691de 100644
--- a/SweetChatService/Models/ImMessageType.cs
+++ b/SweetChatService/Models/ImMessageType.cs
@@ -5,7 +5,8 @@ namespace SweetChatService.Models
     [JsonConverter(typeof(JsonStringEnumConverter))]
     internal enum ImMessageType
     {
-        CHAT,
+        CHAT_PRIVATE,
+        CHAT_GROUP,
         ONLINE,
         HEARTBEAT,
         SYSTEM,
diff --git a/SweetChatService/Program.cs b/SweetChatService/Program.cs
index 82e1cb8..2460cad 100644
--- a/SweetChatService/Program.cs
+++ b/SweetChatService/Program.cs
@@ -12,8 +12,10 @@ var host = Host.CreateDefaultBuilder(args)
     })
     .ConfigureServices((context, services) =>
     {
-        services.AddSingleton<WebSocketMessageHandler>();
-        services.AddSingleton<WebSocketSessionManager>();
+        services.AddSingleton<WsMsgHandler>();
+        services.AddSingleton<WsSessionManager>();
+
+        services.AddSingleton<PrivateChatService>();
 
         services.AddSingleton(FreeSqlSetup.CreateFreeSql(context.Configuration["ConnectionStrings:Default"]));
         services.AddSingleton<UserService>();
@@ -22,18 +24,20 @@ var host = Host.CreateDefaultBuilder(args)
     .AddWebSocketServer(builder =>
     {
         builder
-            //.UseSessionHandler(async (session) =>
-            //{
-            //    Console.WriteLine($"Client connected: {session.SessionID}");
-            //},
-            //async (session, error) =>
-            //{
-            //    Console.WriteLine($"Client disconnected: {session.SessionID}");
-            //})
+            .UseSessionHandler(async (session) =>
+            {
+                
+            },
+            async (session, error) =>
+            {
+                using var scope = session.Server.ServiceProvider.CreateScope();
+                var manager = scope.ServiceProvider.GetRequiredService<WsSessionManager>();
+                manager.RemoveBySession(session.SessionID);
+            })
             .UseWebSocketMessageHandler(async (session, package) =>
             {
                 using var scope = session.Server.ServiceProvider.CreateScope();
-                var handler = scope.ServiceProvider.GetRequiredService<WebSocketMessageHandler>();
+                var handler = scope.ServiceProvider.GetRequiredService<WsMsgHandler>();
 
                 await handler.HandleAsync(session, package);
             })
diff --git a/SweetChatService/Services/PrivateChatService.cs b/SweetChatService/Services/PrivateChatService.cs
new file mode 100644
index 0000000..a78ee10
--- /dev/null
+++ b/SweetChatService/Services/PrivateChatService.cs
@@ -0,0 +1,26 @@
+using SweetChatService.Handlers;
+using SweetChatService.Models;
+
+namespace SweetChatService.Services
+{
+    internal class PrivateChatService(WsSessionManager wsSessionManager)
+    {
+        private readonly WsSessionManager _wsSessionManager = wsSessionManager;
+
+        public async Task HandleAsync(ImMessage msg)
+        {
+            // 推送给对方
+            if (_wsSessionManager.TryGet(msg.To, out var toSession))
+            {
+                await toSession.SendAsync(msg.ToJson());
+            }
+
+
+            // 推送给自己
+            if (_wsSessionManager.TryGet(msg.From, out var fromSession))
+            {
+                await fromSession.SendAsync(msg.ToJson());
+            }
+        }
+    }
+}
diff --git a/SweetChatService/appsettings.json b/SweetChatService/appsettings.json
index 011ef2f..38e2d10 100644
--- a/SweetChatService/appsettings.json
+++ b/SweetChatService/appsettings.json
@@ -1,6 +1,6 @@
 {
   "ConnectionStrings": {
-    "Default": "Server=localhost;Port=3306;Database=sweet_chat;Uid=root;Pwd=123456;Charset=utf8mb4;"
+    "Default": "Server=localhost;Port=3306;Database=sweet_chat;Uid=root;Pwd=estun@medical;Charset=utf8mb4;"
   },
   "serverOptions": {
     "WebSocketServer": {