diff --git a/src/JT809.Protocol/JT809.Protocol.csproj b/src/JT809.Protocol/JT809.Protocol.csproj
index d009509..342b4d7 100644
--- a/src/JT809.Protocol/JT809.Protocol.csproj
+++ b/src/JT809.Protocol/JT809.Protocol.csproj
@@ -4,8 +4,13 @@
     <TargetFramework>netstandard2.0</TargetFramework>
   </PropertyGroup>
 
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
+    <DocumentationFile>bin\Release\netstandard2.0\JT809.Protocol.xml</DocumentationFile>
+  </PropertyGroup>
+
   <ItemGroup>
     <Folder Include="Encrypt\" />
+    <Folder Include="ProtocolPacket\Message\SlaveLink\" />
   </ItemGroup>
 
 </Project>
diff --git a/src/JT809.Protocol/ProtocolPacket/Message/MainLink/MainLink_Login.cs b/src/JT809.Protocol/ProtocolPacket/Message/MainLink/MainLink_Login.cs
new file mode 100644
index 0000000..2331c10
--- /dev/null
+++ b/src/JT809.Protocol/ProtocolPacket/Message/MainLink/MainLink_Login.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace JT809.Protocol.ProtocolPacket.Message.MainLink
+{
+    /// <summary>
+    /// 主链路登录请求消息
+    /// </summary>
+    public sealed class MainLink_Login: MessageBody
+    {
+
+    }
+}
diff --git a/src/JT809.Protocol/ProtocolPacket/MessageBody.cs b/src/JT809.Protocol/ProtocolPacket/MessageBody.cs
new file mode 100644
index 0000000..c19740f
--- /dev/null
+++ b/src/JT809.Protocol/ProtocolPacket/MessageBody.cs
@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace JT809.Protocol.ProtocolPacket
+{
+    /// <summary>
+    /// 抽象消息体 
+    /// </summary>
+    public abstract class MessageBody
+    {
+        public IEncrypt Encrypt { get; set; }
+    }
+}
diff --git a/src/JT809.Protocol/ProtocolPacket/Package.cs b/src/JT809.Protocol/ProtocolPacket/Package.cs
index 452531c..6dc9783 100644
--- a/src/JT809.Protocol/ProtocolPacket/Package.cs
+++ b/src/JT809.Protocol/ProtocolPacket/Package.cs
@@ -13,7 +13,8 @@ namespace JT809.Protocol.ProtocolPacket
         public const int CrcByteLength = 2;
         public const byte BeginFlag = 0X5B;
         public const byte EndFlag = 0X5D;
-        public Header Header { get; private set; }
+        public Header Header { get; set; }
+        public MessageBody MessageBody { get; set; }
         private ushort CRCCheckCode { get; set; }
     }
 }