diff --git a/shadowsocks-csharp/Controller/ShadowsocksController.cs b/shadowsocks-csharp/Controller/ShadowsocksController.cs
index 8d271372..734f27d1 100755
--- a/shadowsocks-csharp/Controller/ShadowsocksController.cs
+++ b/shadowsocks-csharp/Controller/ShadowsocksController.cs
@@ -192,6 +192,28 @@ namespace Shadowsocks.Controller
             }
         }
 
+        public void SavePACUrl(string pacUrl)
+        {
+            _config.pacUrl = pacUrl;
+            UpdateSystemProxy();
+            SaveConfig(_config);
+            if (ConfigChanged != null)
+            {
+                ConfigChanged(this, new EventArgs());
+            }
+        }
+
+        public void UseOnlinePAC(bool useOnlinePac)
+        {
+            _config.useOnlinePac = useOnlinePac;
+            UpdateSystemProxy();
+            SaveConfig(_config);
+            if (ConfigChanged != null)
+            {
+                ConfigChanged(this, new EventArgs());
+            }
+        }
+
         protected void Reload()
         {
             // some logic in configuration updated the config when saving, we need to read it again
diff --git a/shadowsocks-csharp/Controller/SystemProxy.cs b/shadowsocks-csharp/Controller/SystemProxy.cs
index dfbc4bc1..5fe8a244 100755
--- a/shadowsocks-csharp/Controller/SystemProxy.cs
+++ b/shadowsocks-csharp/Controller/SystemProxy.cs
@@ -49,9 +49,14 @@ namespace Shadowsocks.Controller
                     }
                     else
                     {
+                        string pacUrl;
+                        if (config.useOnlinePac && !string.IsNullOrEmpty(config.pacUrl))
+                            pacUrl = config.pacUrl;
+                        else
+                            pacUrl = "http://127.0.0.1:" + config.localPort.ToString() + "/pac?t=" + GetTimestamp(DateTime.Now);
                         registry.SetValue("ProxyEnable", 0);
                         registry.SetValue("ProxyServer", "");
-                        registry.SetValue("AutoConfigURL", "http://127.0.0.1:" + config.localPort.ToString() + "/pac?t=" + GetTimestamp(DateTime.Now));
+                        registry.SetValue("AutoConfigURL", pacUrl);
                     }
                 }
                 else
diff --git a/shadowsocks-csharp/Data/cn.txt b/shadowsocks-csharp/Data/cn.txt
index 486ba27d..22a6478b 100644
--- a/shadowsocks-csharp/Data/cn.txt
+++ b/shadowsocks-csharp/Data/cn.txt
@@ -40,6 +40,13 @@ New server=未配置的服务器
 
 QRCode=二维码
 
+# PAC Url Form
+
+Local PAC=使用本地 PAC
+Online PAC=使用在线 PAC
+Update Online PAC URL=更新在线 PAC 网址
+Please input PAC Url=请输入 PAC 网址
+
 # Messages
 
 Shadowsocks Error: {0}=Shadowsocks 错误: {0}
diff --git a/shadowsocks-csharp/Model/Configuration.cs b/shadowsocks-csharp/Model/Configuration.cs
index 56c91759..b78358e8 100755
--- a/shadowsocks-csharp/Model/Configuration.cs
+++ b/shadowsocks-csharp/Model/Configuration.cs
@@ -17,6 +17,8 @@ namespace Shadowsocks.Model
         public bool shareOverLan;
         public bool isDefault;
         public int localPort;
+        public string pacUrl;
+        public bool useOnlinePac;
 
         private static string CONFIG_FILE = "gui-config.json";
 
diff --git a/shadowsocks-csharp/View/MenuViewController.cs b/shadowsocks-csharp/View/MenuViewController.cs
index 0660f182..53284975 100755
--- a/shadowsocks-csharp/View/MenuViewController.cs
+++ b/shadowsocks-csharp/View/MenuViewController.cs
@@ -35,6 +35,8 @@ namespace Shadowsocks.View
         private MenuItem ServersItem;
         private MenuItem globalModeItem;
         private MenuItem PACModeItem;
+        private MenuItem localPACItem;
+        private MenuItem onlinePACItem;
         private ConfigForm configForm;
         private string _urlToOpen;
 
@@ -151,10 +153,15 @@ namespace Shadowsocks.View
                     CreateMenuItem("Show QRCode...", new EventHandler(this.QRCodeItem_Click)),
                     CreateMenuItem("Scan QRCode from Screen...", new EventHandler(this.ScanQRCodeItem_Click))
                 }),
-                new MenuItem("-"),
-                CreateMenuItem("Edit PAC File...", new EventHandler(this.EditPACFileItem_Click)),
-                CreateMenuItem("Update PAC from GFWList", new EventHandler(this.UpdatePACFromGFWListItem_Click)),
-                CreateMenuItem("Edit User Rule for GFWList...", new EventHandler(this.EditUserRuleFileForGFWListItem_Click)),
+                CreateMenuGroup("PAC", new MenuItem[] {
+                    this.localPACItem = CreateMenuItem("Local PAC", new EventHandler(this.LocalPACItem_Click)),
+                    this.onlinePACItem = CreateMenuItem("Online PAC", new EventHandler(this.OnlinePACItem_Click)),
+                    new MenuItem("-"),
+                    CreateMenuItem("Edit PAC File...", new EventHandler(this.EditPACFileItem_Click)),
+                    CreateMenuItem("Update PAC from GFWList", new EventHandler(this.UpdatePACFromGFWListItem_Click)),
+                    CreateMenuItem("Edit User Rule for GFWList...", new EventHandler(this.EditUserRuleFileForGFWListItem_Click)),
+                    CreateMenuItem("Update Online PAC URL", new EventHandler(this.UpdateOnlinePACURLItem_Click)),
+                }),
                 new MenuItem("-"),
                 this.AutoStartupItem = CreateMenuItem("Start on Boot", new EventHandler(this.AutoStartupItem_Click)),
                 this.ShareOverLANItem = CreateMenuItem("Allow Clients from LAN", new EventHandler(this.ShareOverLANItem_Click)),
@@ -240,6 +247,9 @@ namespace Shadowsocks.View
             PACModeItem.Checked = !config.global;
             ShareOverLANItem.Checked = config.shareOverLan;
             AutoStartupItem.Checked = AutoStartup.Check();
+            onlinePACItem.Enabled = !string.IsNullOrEmpty(config.pacUrl);
+            onlinePACItem.Checked = onlinePACItem.Enabled && config.useOnlinePac;
+            localPACItem.Checked = !onlinePACItem.Checked;
         }
 
         private void UpdateServersMenu()
@@ -481,5 +491,38 @@ namespace Shadowsocks.View
 				MessageBox.Show(I18N.GetString("Failed to update registry"));
 			}
 		}
+
+        private void LocalPACItem_Click(object sender, EventArgs e)
+        {
+            if (!localPACItem.Checked)
+            {
+                localPACItem.Checked = true;
+                onlinePACItem.Checked = false;
+                controller.UseOnlinePAC(false);
+            }
+        }
+
+        private void OnlinePACItem_Click(object sender, EventArgs e)
+        {
+            if (!onlinePACItem.Checked)
+            {
+                localPACItem.Checked = false;
+                onlinePACItem.Checked = true;
+                controller.UseOnlinePAC(true);
+            }
+        }
+
+        private void UpdateOnlinePACURLItem_Click(object sender, EventArgs e)
+        {
+            string origPacUrl = controller.GetConfiguration().pacUrl;
+            string pacUrl = Microsoft.VisualBasic.Interaction.InputBox(
+                I18N.GetString("Please input PAC Url"),
+                I18N.GetString("Update Online PAC URL"),
+                origPacUrl, -1, -1);
+            if (!string.IsNullOrEmpty(pacUrl) && pacUrl != origPacUrl)
+            {
+                controller.SavePACUrl(pacUrl);
+            }
+        }
     }
 }
diff --git a/shadowsocks-csharp/shadowsocks-csharp.csproj b/shadowsocks-csharp/shadowsocks-csharp.csproj
index fd849f85..aa2c9000 100755
--- a/shadowsocks-csharp/shadowsocks-csharp.csproj
+++ b/shadowsocks-csharp/shadowsocks-csharp.csproj
@@ -63,6 +63,7 @@
     <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
   <ItemGroup>
+    <Reference Include="Microsoft.VisualBasic" />
     <Reference Include="System" />
     <Reference Include="System.Data" />
     <Reference Include="System.Drawing" />