diff --git a/v2rayN/ServiceLib/Models/SingboxConfig.cs b/v2rayN/ServiceLib/Models/SingboxConfig.cs
index f2331cc4..000097bb 100644
--- a/v2rayN/ServiceLib/Models/SingboxConfig.cs
+++ b/v2rayN/ServiceLib/Models/SingboxConfig.cs
@@ -237,6 +237,8 @@ public class Transport4Sbox
 public class Headers4Sbox
 {
     public string? Host { get; set; }
+    [JsonPropertyName("User-Agent")]
+    public string UserAgent { get; set; }
 }
 
 public class HyObfs4Sbox
diff --git a/v2rayN/ServiceLib/Resx/ResUI.Designer.cs b/v2rayN/ServiceLib/Resx/ResUI.Designer.cs
index c64b7402..d323889a 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.Designer.cs
+++ b/v2rayN/ServiceLib/Resx/ResUI.Designer.cs
@@ -3772,7 +3772,7 @@ namespace ServiceLib.Resx {
         }
         
         /// <summary>
-        ///   查找类似 This parameter is valid only for tcp/http and ws 的本地化字符串。
+        ///   查找类似 This parameter is valid only for tcp/http, ws, gRPC and xhttp 的本地化字符串。
         /// </summary>
         public static string TbSettingsDefUserAgentTips {
             get {
diff --git a/v2rayN/ServiceLib/Resx/ResUI.fa-Ir.resx b/v2rayN/ServiceLib/Resx/ResUI.fa-Ir.resx
index 56e7bd5c..eda45653 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.fa-Ir.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.fa-Ir.resx
@@ -937,7 +937,7 @@
     <value>User-Agent</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>این پارامتر فقط برای tcp/http و ws معتبر است</value>
+    <value>This parameter is valid only for tcp/http, ws, gRPC and xhttp</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>FontFamily (نیاز به راه اندازی مجدد)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.fr.resx b/v2rayN/ServiceLib/Resx/ResUI.fr.resx
index 9e81a7c9..8f173e6e 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.fr.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.fr.resx
@@ -937,7 +937,7 @@
     <value>Agent utilisateur (User-Agent)</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>Valable uniquement pour les protocoles tcp/http et ws</value>
+    <value>This parameter is valid only for tcp/http, ws, gRPC and xhttp</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>Police actuelle (redémarrage requis)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.hu.resx b/v2rayN/ServiceLib/Resx/ResUI.hu.resx
index 8f64e04b..4437eafa 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.hu.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.hu.resx
@@ -937,7 +937,7 @@
     <value>User-Agent</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>Ez a paraméter csak tcp/http és ws esetén érvényes</value>
+    <value>This parameter is valid only for tcp/http, ws, gRPC and xhttp</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>Betűtípus (újraindítást igényel)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.resx b/v2rayN/ServiceLib/Resx/ResUI.resx
index 3b21ec73..6bbf3f72 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.resx
@@ -937,7 +937,7 @@
     <value>User-Agent</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>This parameter is valid only for tcp/http and ws</value>
+    <value>This parameter is valid only for tcp/http, ws, gRPC and xhttp</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>Font family (requires restart)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.ru.resx b/v2rayN/ServiceLib/Resx/ResUI.ru.resx
index 86a613c3..c777c4d9 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.ru.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.ru.resx
@@ -937,7 +937,7 @@
     <value>User-Agent</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>Параметр действует только для TCP/HTTP и WebSocket (WS)</value>
+    <value>This parameter is valid only for tcp/http, ws, gRPC and xhttp</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>Шрифт (требуется перезапуск)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.zh-Hans.resx b/v2rayN/ServiceLib/Resx/ResUI.zh-Hans.resx
index 36e5efc0..b26059ad 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.zh-Hans.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.zh-Hans.resx
@@ -937,7 +937,7 @@
     <value>用户代理 (User-Agent)</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>仅对 tcp/http、ws 协议生效</value>
+    <value>仅对 tcp/http、ws、gRPC、xhttp 生效</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>当前字体 (需重启)</value>
diff --git a/v2rayN/ServiceLib/Resx/ResUI.zh-Hant.resx b/v2rayN/ServiceLib/Resx/ResUI.zh-Hant.resx
index be707759..bacf2f11 100644
--- a/v2rayN/ServiceLib/Resx/ResUI.zh-Hant.resx
+++ b/v2rayN/ServiceLib/Resx/ResUI.zh-Hant.resx
@@ -937,7 +937,7 @@
     <value>使用者代理 (User-Agent)</value>
   </data>
   <data name="TbSettingsDefUserAgentTips" xml:space="preserve">
-    <value>僅對 TCP/HTTP、WS 協定生效</value>
+    <value>僅對 TCP/HTTP、WS、gRPC、XHTTP 生效</value>
   </data>
   <data name="TbSettingsCurrentFontFamily" xml:space="preserve">
     <value>目前字型 (需重啟)</value>
diff --git a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxOutboundService.cs b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxOutboundService.cs
index 7a86761f..34a7f49f 100644
--- a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxOutboundService.cs
+++ b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxOutboundService.cs
@@ -438,6 +438,8 @@ public partial class CoreConfigSingboxService
         try
         {
             var transport = new Transport4Sbox();
+            var useragent = _config.CoreBasicItem.DefUserAgent ?? string.Empty;
+            var useragentValue = Global.TcpHttpUserAgentTexts.GetValueOrDefault(useragent, useragent);
 
             switch (_node.GetNetwork())
             {
@@ -453,6 +455,11 @@ public partial class CoreConfigSingboxService
                         transport.type = nameof(ETransport.http);
                         transport.host = _node.RequestHost.IsNullOrEmpty() ? null : Utils.String2List(_node.RequestHost);
                         transport.path = _node.Path.NullIfEmpty();
+                        if (!useragentValue.IsNullOrEmpty())
+                        {
+                            transport.headers ??= new();
+                            transport.headers.UserAgent = useragentValue;
+                        }
                     }
                     break;
 
@@ -494,12 +501,22 @@ public partial class CoreConfigSingboxService
                             Host = _node.RequestHost
                         };
                     }
+                    if (!useragentValue.IsNullOrEmpty())
+                    {
+                        transport.headers ??= new();
+                        transport.headers.UserAgent = useragentValue;
+                    }
                     break;
 
                 case nameof(ETransport.httpupgrade):
                     transport.type = nameof(ETransport.httpupgrade);
                     transport.path = _node.Path.NullIfEmpty();
                     transport.host = _node.RequestHost.NullIfEmpty();
+                    if (!useragentValue.IsNullOrEmpty())
+                    {
+                        transport.headers ??= new();
+                        transport.headers.UserAgent = useragentValue;
+                    }
 
                     break;