diff --git a/v2rayN/v2rayN/Handler/CoreConfigHandler.cs b/v2rayN/v2rayN/Handler/CoreConfigHandler.cs
index 8ccfc38a..86617d8c 100644
--- a/v2rayN/v2rayN/Handler/CoreConfigHandler.cs
+++ b/v2rayN/v2rayN/Handler/CoreConfigHandler.cs
@@ -547,13 +547,16 @@ namespace v2rayN.Handler
                 string host = node.requestHost.TrimEx();
                 string sni = node.sni;
                 string useragent = "";
-                if (!config.customizeUserAgent.IsNullOrEmpty())
+                if (!config.defUserAgent.IsNullOrEmpty())
                 {
-                    useragent = config.customizeUserAgent;
-                }
-                else if (!config.defUserAgent.IsNullOrEmpty())
-                {
-                    useragent = Global.userAgentTxt[config.defUserAgent];
+                    try
+                    {
+                        useragent = Global.userAgentTxt[config.defUserAgent];
+                    }
+                    catch (KeyNotFoundException)
+                    {
+                        useragent = config.defUserAgent;
+                    }
                 }
 
                 //if tls
diff --git a/v2rayN/v2rayN/Mode/Config.cs b/v2rayN/v2rayN/Mode/Config.cs
index b6dc9fcc..0166d894 100644
--- a/v2rayN/v2rayN/Mode/Config.cs
+++ b/v2rayN/v2rayN/Mode/Config.cs
@@ -99,8 +99,6 @@
         /// </summary>
         public string defUserAgent { get; set; }
 
-        public string customizeUserAgent { get; set; }
-
         /// <summary>
         /// 域名解析策略
         /// </summary>
diff --git a/v2rayN/v2rayN/Resx/ResUI.Designer.cs b/v2rayN/v2rayN/Resx/ResUI.Designer.cs
index 1ef9e227..8597560f 100644
--- a/v2rayN/v2rayN/Resx/ResUI.Designer.cs
+++ b/v2rayN/v2rayN/Resx/ResUI.Designer.cs
@@ -2392,15 +2392,6 @@ namespace v2rayN.Resx {
             }
         }
         
-        /// <summary>
-        ///   查找类似 Customize User-Agent 的本地化字符串。
-        /// </summary>
-        public static string TbSettingsCustomizeUserAgent {
-            get {
-                return ResourceManager.GetString("TbSettingsCustomizeUserAgent", resourceCulture);
-            }
-        }
-        
         /// <summary>
         ///   查找类似 AllowInsecure 的本地化字符串。
         /// </summary>
@@ -2428,6 +2419,15 @@ namespace v2rayN.Resx {
             }
         }
         
+        /// <summary>
+        ///   查找类似 This parameter is valid only for tcp/http and ws 的本地化字符串。
+        /// </summary>
+        public static string TbSettingsDefUserAgentTips {
+            get {
+                return ResourceManager.GetString("TbSettingsDefUserAgentTips", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   查找类似 Outbound Freedom domainStrategy 的本地化字符串。
         /// </summary>
diff --git a/v2rayN/v2rayN/Resx/ResUI.fa-Ir.resx b/v2rayN/v2rayN/Resx/ResUI.fa-Ir.resx
index 4b3744f6..9008d82d 100644
--- a/v2rayN/v2rayN/Resx/ResUI.fa-Ir.resx
+++ b/v2rayN/v2rayN/Resx/ResUI.fa-Ir.resx
@@ -1060,10 +1060,10 @@
   <data name="TbSettingsTunModeShowWindow" xml:space="preserve">
     <value>نمایش کنسول</value>
   </data>
-  <data name="TbSettingsCustomizeUserAgent" xml:space="preserve">
-    <value>Customize User-Agent</value>
-  </data>
   <data name="TbSettingsDefUserAgent" xml:space="preserve">
     <value>User-Agent</value>
   </data>
+  <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
+    <value>This parameter is valid only for tcp/http and ws</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/v2rayN/v2rayN/Resx/ResUI.resx b/v2rayN/v2rayN/Resx/ResUI.resx
index 5dc3a280..cfa575dd 100644
--- a/v2rayN/v2rayN/Resx/ResUI.resx
+++ b/v2rayN/v2rayN/Resx/ResUI.resx
@@ -1087,10 +1087,10 @@
   <data name="TbSettingsDefFingerprint" xml:space="preserve">
     <value>Default TLS fingerprint</value>
   </data>
-  <data name="TbSettingsCustomizeUserAgent" xml:space="preserve">
-    <value>Customize User-Agent</value>
-  </data>
   <data name="TbSettingsDefUserAgent" xml:space="preserve">
     <value>User-Agent</value>
   </data>
+  <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
+    <value>This parameter is valid only for tcp/http and ws</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/v2rayN/v2rayN/Resx/ResUI.zh-Hans.resx b/v2rayN/v2rayN/Resx/ResUI.zh-Hans.resx
index cbce7200..f27e18bd 100644
--- a/v2rayN/v2rayN/Resx/ResUI.zh-Hans.resx
+++ b/v2rayN/v2rayN/Resx/ResUI.zh-Hans.resx
@@ -1087,10 +1087,10 @@
   <data name="TbSettingsDefFingerprint" xml:space="preserve">
     <value>默认TLS指纹(fingerprint)</value>
   </data>
-  <data name="TbSettingsCustomizeUserAgent" xml:space="preserve">
-    <value>自定义用户代理(UA)</value>
-  </data>
   <data name="TbSettingsDefUserAgent" xml:space="preserve">
     <value>用户代理(UA)</value>
   </data>
+  <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
+    <value>仅对tcp/http、ws协议生效</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/v2rayN/v2rayN/ViewModels/OptionSettingViewModel.cs b/v2rayN/v2rayN/ViewModels/OptionSettingViewModel.cs
index 746f5189..d532dba0 100644
--- a/v2rayN/v2rayN/ViewModels/OptionSettingViewModel.cs
+++ b/v2rayN/v2rayN/ViewModels/OptionSettingViewModel.cs
@@ -30,7 +30,6 @@ namespace v2rayN.ViewModels
         [Reactive] public bool defAllowInsecure { get; set; }
         [Reactive] public string defFingerprint { get; set; }
         [Reactive] public string defUserAgent { get; set; }
-        [Reactive] public string customizeUserAgent { get; set; }
         #endregion
 
         #region Core DNS
@@ -115,7 +114,6 @@ namespace v2rayN.ViewModels
             defAllowInsecure = _config.defAllowInsecure;
             defFingerprint = _config.defFingerprint;
             defUserAgent = _config.defUserAgent;
-            customizeUserAgent = _config.customizeUserAgent;
             #endregion
 
             #region Core DNS
@@ -277,7 +275,6 @@ namespace v2rayN.ViewModels
             _config.defAllowInsecure = defAllowInsecure;
             _config.defFingerprint = defFingerprint;
             _config.defUserAgent = defUserAgent;
-            _config.customizeUserAgent = customizeUserAgent;
 
 
             //DNS
diff --git a/v2rayN/v2rayN/Views/OptionSettingWindow.xaml b/v2rayN/v2rayN/Views/OptionSettingWindow.xaml
index 6be18fe6..72dd0f6e 100644
--- a/v2rayN/v2rayN/Views/OptionSettingWindow.xaml
+++ b/v2rayN/v2rayN/Views/OptionSettingWindow.xaml
@@ -70,6 +70,7 @@
                         <Grid.ColumnDefinitions>
                             <ColumnDefinition Width="Auto" />
                             <ColumnDefinition Width="Auto" />
+                            <ColumnDefinition Width="Auto" />
                         </Grid.ColumnDefinitions>
 
                         <TextBlock
@@ -264,21 +265,13 @@
                         x:Name="cmbdefUserAgent"
                         Grid.Row="13"
                         Grid.Column="1"
-                        Margin="{StaticResource SettingItemMargin}" />
-
+                        Margin="{StaticResource SettingItemMargin}" IsEditable="True" />
                         <TextBlock
-                        Grid.Row="14"
-                        Grid.Column="0"
+                        Grid.Row="13"
+                        Grid.Column="3"
                         Margin="{StaticResource SettingItemMargin}"
-                        VerticalAlignment="Center"
                         Style="{StaticResource ToolbarTextBlock}"
-                        Text="{x:Static resx:ResUI.TbSettingsCustomizeUserAgent}" />
-                        <TextBox
-                        x:Name="txtcustomizeUserAgent"
-                        Grid.Row="14"
-                        Grid.Column="1"
-                        Width="200"
-                        Margin="{StaticResource SettingItemMargin}" />
+                        Text="{x:Static resx:ResUI.TbSettingsDefUserAgentTips}" />
                     </Grid>
                 </ScrollViewer>
             </TabItem>
diff --git a/v2rayN/v2rayN/Views/OptionSettingWindow.xaml.cs b/v2rayN/v2rayN/Views/OptionSettingWindow.xaml.cs
index eade2567..639adb31 100644
--- a/v2rayN/v2rayN/Views/OptionSettingWindow.xaml.cs
+++ b/v2rayN/v2rayN/Views/OptionSettingWindow.xaml.cs
@@ -73,7 +73,6 @@ namespace v2rayN.Views
                 this.Bind(ViewModel, vm => vm.defAllowInsecure, v => v.togdefAllowInsecure.IsChecked).DisposeWith(disposables);
                 this.Bind(ViewModel, vm => vm.defFingerprint, v => v.cmbdefFingerprint.Text).DisposeWith(disposables);
                 this.Bind(ViewModel, vm => vm.defUserAgent, v => v.cmbdefUserAgent.Text).DisposeWith(disposables);
-                this.Bind(ViewModel, vm => vm.customizeUserAgent, v => v.txtcustomizeUserAgent.Text).DisposeWith(disposables);
 
 
                 this.Bind(ViewModel, vm => vm.domainStrategy4Freedom, v => v.cmbdomainStrategy4Freedom.Text).DisposeWith(disposables);