diff --git a/src/JT809.Protocol/ProtocolPacket/Header.cs b/src/JT809.Protocol/ProtocolPacket/Header.cs
index abfc0d9..b5afd0d 100644
--- a/src/JT809.Protocol/ProtocolPacket/Header.cs
+++ b/src/JT809.Protocol/ProtocolPacket/Header.cs
@@ -1,6 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
 
 namespace JT809.Protocol.ProtocolPacket
 {
@@ -9,7 +7,43 @@ namespace JT809.Protocol.ProtocolPacket
     /// </summary>
     public class Header
     {
+        /// <summary>
+        /// 固定为22个字节长度
+        /// </summary>
+        public const int HeaderFixedByteLength = 22;
+        /// <summary>
+        /// 发送计数器
+        /// 占用四个字节，为发送信息的序列号，用于接收方检测是否有信息的丢失，上级平台和下级平台接自己发送数据包的个数计数，互不影响。
+        /// 程序开始运行时等于零，发送第一帧数据时开始计数，到最大数后自动归零
+        /// </summary>
+        public static uint CounterOnSendGenerater { get; private set; }
+        /// <summary>
+        /// 接收计数器
+        /// 占用四个字节，为发送信息的序列号，用于接收方检测是否有信息的丢失，上级平台和下级平台接自己发送数据包的个数计数，互不影响。
+        /// 程序开始运行时等于零，发送第一帧数据时开始计数，到最大数后自动归零
+        /// </summary>
+        public static uint CounterOnRecieveGenerater { get; private set; }
+        /// <summary>
+        /// 数据长度(包括头标识、数据头、数据体和尾标识)
+        /// </summary>
+        public uint Length { get; private set; }
+        /// <summary>
+        /// 报文序列号
+        /// </summary>
+        public uint SN { get; private set; }
+        /// <summary>
+        /// 业务数据类型
+        /// </summary>
+        public ushort BusinessID { get; private set; }
+        /// <summary>
+        /// 下级平台接入码，上级平台给下级平台分配唯一标识码。
+        /// </summary>
+        public uint GNSSCENTERID { get; set; }
         public Version Version { get; private set; }
         public EncryptEnum EncryptEnum { get; private set; }
+        /// <summary>
+        /// 数据加密的密匙，长度为 4 个字节。
+        /// </summary>
+        public uint EncryptKey { get; private set; } = 0X00;
     }
 }
diff --git a/src/JT809.Protocol/ProtocolPacket/Package.cs b/src/JT809.Protocol/ProtocolPacket/Package.cs
new file mode 100644
index 0000000..452531c
--- /dev/null
+++ b/src/JT809.Protocol/ProtocolPacket/Package.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace JT809.Protocol.ProtocolPacket
+{
+    /// <summary>
+    /// 数据包
+    /// </summary>
+    public class Package
+    {
+        public const int NotDataLength = 26;
+        public const int CrcByteLength = 2;
+        public const byte BeginFlag = 0X5B;
+        public const byte EndFlag = 0X5D;
+        public Header Header { get; private set; }
+        private ushort CRCCheckCode { get; set; }
+    }
+}