diff --git a/Netch/Controllers/HTTPController.cs b/Netch/Controllers/HTTPController.cs
index e880bac0..0963ff29 100644
--- a/Netch/Controllers/HTTPController.cs
+++ b/Netch/Controllers/HTTPController.cs
@@ -3,6 +3,7 @@ using WindowsProxy;
 using Netch.Models;
 using Netch.Servers.Socks5;
 using Netch.Servers.Trojan;
+using Netch.Utils;
 using Netch.Utils.HttpProxyHandler;
 
 namespace Netch.Controllers
@@ -24,16 +25,30 @@ namespace Netch.Controllers
         {
             PrivoxyController.Start(MainController.Server!);
             Global.Job.AddProcess(PrivoxyController.Instance!);
+            string? pacUrl = null;
+
+            if (MainController.Server is Socks5 or Trojan && mode.BypassChina || (Global.Settings.AlwaysStartPACServer ?? false))
+            {
+                try
+                {
+                    PortHelper.CheckPort(Global.Settings.Pac_Port);
+                }
+                catch
+                {
+                    Global.Settings.Pac_Port = PortHelper.GetAvailablePort();
+                }
+
+                pacUrl = PACServerHandle.InitPACServer("127.0.0.1");
+            }
 
             if (mode.Type is 3)
             {
                 using var service = new ProxyService();
                 _oldState = service.Query();
 
-                if (MainController.Server is Socks5 or Trojan && mode.BypassChina)
+                if (pacUrl != null)
                 {
-                    service.AutoConfigUrl = PACServerHandle.InitPACServer("127.0.0.1");
-
+                    service.AutoConfigUrl = pacUrl;
                     service.Pac();
                 }
                 else
diff --git a/Netch/Models/Setting.cs b/Netch/Models/Setting.cs
index a2c4414e..0e7b3912 100644
--- a/Netch/Models/Setting.cs
+++ b/Netch/Models/Setting.cs
@@ -174,7 +174,7 @@ namespace Netch.Models
         /// <summary>
         ///     PAC端口
         /// </summary>
-        public int Pac_Port { get; set; } = 2803;
+        public ushort Pac_Port { get; set; } = 2803;
 
         /// <summary>
         ///     不代理TCP
@@ -293,6 +293,8 @@ namespace Netch.Models
 
         public V2rayConfig V2RayConfig { get; set; } = new();
 
+        public bool? AlwaysStartPACServer { get; set; }
+
         public Setting Clone()
         {
             return (Setting) MemberwiseClone();
diff --git a/Netch/Utils/HttpProxyHandler/HttpWebServer.cs b/Netch/Utils/HttpProxyHandler/HttpWebServer.cs
index 30c4ccbe..00ad981a 100644
--- a/Netch/Utils/HttpProxyHandler/HttpWebServer.cs
+++ b/Netch/Utils/HttpProxyHandler/HttpWebServer.cs
@@ -1,85 +1,67 @@
 using System;
 using System.Net;
 using System.Text;
-using System.Threading;
 
 namespace Netch.Utils.HttpProxyHandler
 {
     public class HttpWebServer
     {
-        private HttpListener? _listener;
         private readonly Func<HttpListenerRequest, string>? _responderMethod;
+        private HttpListener? _listener;
 
         public HttpWebServer(string[] prefixes, Func<HttpListenerRequest, string> method)
         {
-            try
-            {
-                _listener = new HttpListener();
+            _listener = new HttpListener();
 
-                if (!HttpListener.IsSupported)
-                    throw new NotSupportedException("Needs Windows XP SP2, Server 2003 or later.");
+            // URI prefixes are required, for example 
+            // "http://localhost:8080/index/".
+            if (prefixes == null || prefixes.Length == 0)
+                throw new ArgumentException("prefixes");
 
-                // URI prefixes are required, for example 
-                // "http://localhost:8080/index/".
-                if (prefixes == null || prefixes.Length == 0)
-                    throw new ArgumentException("prefixes");
+            // A responder method is required
+            if (method == null)
+                throw new ArgumentException("method");
 
-                // A responder method is required
-                if (method == null)
-                    throw new ArgumentException("method");
+            foreach (var s in prefixes)
+                _listener.Prefixes.Add(s);
 
-                foreach (var s in prefixes)
-                    _listener.Prefixes.Add(s);
-
-                _responderMethod = method;
-                _listener.Start();
-            }
-            catch (Exception ex)
-            {
-                Logging.Error("HttpWebServer():" + ex.Message);
-            }
+            _responderMethod = method;
+            _listener.Start();
         }
 
         public HttpWebServer(Func<HttpListenerRequest, string> method, params string[] prefixes) : this(prefixes, method)
         {
         }
 
-        public void Run()
+        public void StartWaitingRequest()
         {
-            ThreadPool.QueueUserWorkItem(o =>
+            Logging.Info("Webserver running...");
+            while (_listener?.IsListening ?? false)
             {
-                Logging.Info("Webserver running...");
+                HttpListenerContext ctx;
                 try
                 {
-                    while (_listener!.IsListening)
-                        ThreadPool.QueueUserWorkItem(c =>
-                            {
-                                var ctx = (HttpListenerContext) c;
-                                try
-                                {
-                                    var rstr = _responderMethod!(ctx.Request);
-                                    var buf = Encoding.UTF8.GetBytes(rstr);
-                                    ctx.Response.StatusCode = 200;
-                                    ctx.Response.ContentType = "application/x-ns-proxy-autoconfig";
-                                    ctx.Response.ContentLength64 = buf.Length;
-                                    ctx.Response.OutputStream.Write(buf, 0, buf.Length);
-                                }
-                                catch
-                                {
-                                    // ignored
-                                }
-                                finally
-                                {
-                                    ctx.Response.OutputStream.Close();
-                                }
-                            },
-                            _listener.GetContext());
+                    ctx = _listener.GetContext();
                 }
-                catch (Exception ex)
+                catch
                 {
-                    Logging.Error(ex.Message);
+                    break;
                 }
-            });
+
+                try
+                {
+                    var rstr = _responderMethod!(ctx.Request);
+                    var buf = Encoding.UTF8.GetBytes(rstr);
+                    ctx.Response.StatusCode = 200;
+                    ctx.Response.ContentType = "application/x-ns-proxy-autoconfig";
+                    ctx.Response.ContentLength64 = buf.Length;
+                    ctx.Response.OutputStream.Write(buf, 0, buf.Length);
+                }
+                finally
+                {
+                    ctx.Response.OutputStream.Close();
+                }
+            }
         }
 
         public void Stop()
diff --git a/Netch/Utils/HttpProxyHandler/PACServerHandle.cs b/Netch/Utils/HttpProxyHandler/PACServerHandle.cs
index d4e925fc..c252233a 100644
--- a/Netch/Utils/HttpProxyHandler/PACServerHandle.cs
+++ b/Netch/Utils/HttpProxyHandler/PACServerHandle.cs
@@ -1,102 +1,74 @@
 using System;
-using System.Collections;
-using System.Collections.Generic;
 using System.IO;
 using System.Net;
 using System.Text;
+using System.Threading.Tasks;
+using Netch.Controllers;
 
 namespace Netch.Utils.HttpProxyHandler
 {
     /// <summary>
     ///     提供PAC功能支持
     /// </summary>
-    internal class PACServerHandle
+    internal static class PACServerHandle
     {
-        private static readonly Hashtable httpWebServer = new();
-        private static readonly Hashtable pacList = new();
+        private static HttpWebServer? _httpWebServer;
+        private static string? _pacContent;
 
         public static string InitPACServer(string address)
         {
             try
             {
-                if (!pacList.ContainsKey(address))
-                    pacList.Add(address, GetPacList(address));
-
+                _pacContent = GetPacList(address);
                 var prefixes = $"http://{address}:{Global.Settings.Pac_Port}/pac/";
 
-                var ws = new HttpWebServer(SendResponse, prefixes);
-                ws.Run();
-
-                if (!httpWebServer.ContainsKey(address))
-                    httpWebServer.Add(address, ws);
+                _httpWebServer = new HttpWebServer(SendResponse, prefixes);
+                Task.Run(() => _httpWebServer.StartWaitingRequest());
 
                 var pacUrl = GetPacUrl();
                 Logging.Info($"Webserver InitServer OK: {pacUrl}");
                 return pacUrl;
             }
-            catch (Exception ex)
+            catch
             {
-                throw new Exception("Webserver InitServer Error:" + ex.Message);
+                Logging.Error("Webserver InitServer Failed");
+                throw;
             }
         }
 
         public static string SendResponse(HttpListenerRequest request)
         {
-            try
-            {
-                var arrAddress = request.UserHostAddress.Split(':');
-                var address = "127.0.0.1";
-                if (arrAddress.Length > 0)
-                    address = arrAddress[0];
-
-                return pacList[address].ToString();
-            }
-            catch (Exception ex)
-            {
-                Logging.Error("Webserver SendResponse " + ex.Message);
-                return ex.Message;
-            }
+            return _pacContent!;
         }
 
         public static void Stop()
         {
             try
             {
-                if (httpWebServer == null)
-                    return;
-
-                foreach (var key in httpWebServer.Keys)
-                {
-                    Logging.Info("Webserver Stop " + key);
-                    ((HttpWebServer) httpWebServer[key]).Stop();
-                }
-
-                httpWebServer.Clear();
+                _httpWebServer?.Stop();
             }
-            catch (Exception ex)
+            catch
             {
-                Logging.Error("Webserver Stop " + ex.Message);
+                // ignored
             }
+
+            _httpWebServer = null;
         }
 
         private static string GetPacList(string address)
         {
             try
             {
-                var lstProxy = new List<string>();
-                lstProxy.Add(string.Format("PROXY {0}:{1};", address, Global.Settings.HTTPLocalPort));
+                var proxy = $"PROXY {address}:{Global.Settings.HTTPLocalPort};";
+                var pacfile = Path.Combine(Global.NetchDir, "bin\\pac.txt");
 
-                var proxy = string.Join("", lstProxy.ToArray());
-                var strPacfile = Path.Combine(Global.NetchDir, "bin\\pac.txt");
-
-                var pac = File.ReadAllText(strPacfile, Encoding.UTF8).Replace("__PROXY__", proxy);
+                var pac = File.ReadAllText(pacfile, Encoding.UTF8).Replace("__PROXY__", proxy);
                 return pac;
             }
             catch
             {
+                throw new MessageException("Pac file not found!");
             }
-
-            return "No pac content";
         }
 
         /// <summary>
@@ -105,9 +77,7 @@ namespace Netch.Utils.HttpProxyHandler
         /// <returns></returns>
         public static string GetPacUrl()
         {
-            var pacUrl = string.Format("http://127.0.0.1:{0}/pac/?t={1}", Global.Settings.Pac_Port, DateTime.Now.ToString("yyyyMMddHHmmssfff"));
-
-            return pacUrl;
+            return $"http://127.0.0.1:{Global.Settings.Pac_Port}/pac/?t={DateTime.Now:yyyyMMddHHmmssfff}";
         }
     }
 }
\ No newline at end of file