diff --git a/src/main/java/component/NackHeader.java b/src/main/java/component/NackHeader.java
index ae233ae..fa65ed9 100644
--- a/src/main/java/component/NackHeader.java
+++ b/src/main/java/component/NackHeader.java
@@ -12,6 +12,10 @@ import encoding.*;
 public class NackHeader implements TlvComponentBase,InitialAble, IEncodingAble {
     // 变量
     private long nackReason;
+    // NackReason 定义
+    public static final long NackReasonUnknown  = 0;
+    public static final long NackReasonDuplicate= 1;
+    public static final long NackReasonNoRoute  = 2;
 
     // 函数
     public long getNackReason() {
diff --git a/src/test/java/component/NackHeaderTest.java b/src/test/java/component/NackHeaderTest.java
new file mode 100644
index 0000000..2362428
--- /dev/null
+++ b/src/test/java/component/NackHeaderTest.java
@@ -0,0 +1,50 @@
+package component;
+
+import encoding.*;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+/*
+ * @Author: Wang Feng
+ * @Description:
+ * @Version: 1.0.0
+ * @Date: 15:20 2021/3/25
+ * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
+ */
+public class NackHeaderTest {
+    @Test
+    public void TestNackHeader_GetNackReason(){
+        NackHeader nackHeader=new NackHeader();
+        System.out.println(nackHeader.getNackReason());
+    }
+
+    @Test
+    public void TestNackHeader_SetNackReason(){
+        NackHeader nackHeader=new NackHeader();
+        nackHeader.setNackReason(12313145641635L);
+        System.out.println(nackHeader.getNackReason());
+    }
+
+    @Test
+    public void TestNackHeader_WireEncode() throws EncoderException, ComponentException {
+        NackHeader nackHeader=new NackHeader();
+        nackHeader.setNackReason(12313145641635L);
+        System.out.println(nackHeader.getNackReason());
+        Encoder encoder=new Encoder();
+        encoder.encoderReset(new SizeT(Encoder.MaxPacketSize),new SizeT(0));
+        nackHeader.wireEncode(encoder);
+        byte[] buffer=encoder.getBuffer();
+        System.out.println("nack buf: "+ Arrays.toString(buffer));
+    }
+
+    @Test
+    public void TestNackHeader_WireDecode() throws BlockException, ComponentException {
+        byte[] buf={(byte)213, (byte)8, (byte)0, (byte)0,
+                (byte)11, (byte)50, (byte)224, (byte)172, (byte)10, (byte)163};
+        Block block=Block.createBlockByBuffer(buf,false);
+        NackHeader nackHeader=new NackHeader();
+        nackHeader.wireDecode(block);
+        System.out.println("nack: "+nackHeader.getNackReason());
+    }
+}