diff --git a/src/main/java/encoding/VlInt.java b/src/main/java/encoding/VlInt.java
index 3900043..108beaa 100644
--- a/src/main/java/encoding/VlInt.java
+++ b/src/main/java/encoding/VlInt.java
@@ -39,6 +39,10 @@ public class VlInt {
     public static final int VlIntSize5=5;
     public static final int VlIntSize9=9;
 
+    public static final long uint16Max= (long) (pow(2, 16)-1);
+    public static final long uint32Max= (long) (pow(2, 32)-1);
+    public static final long uint64Max= Long.MAX_VALUE; //MIN1.0中此数用long的最大值表示
+
     /**
      * 测量一个变长整型实际用几个字节表示
      * @return
@@ -52,15 +56,11 @@ public class VlInt {
         }
         if(bigInteger.compareTo(BigInteger.valueOf(241)) < 0){
             return 1;
-        }else if(bigInteger.compareTo(BigInteger.valueOf(
-                new Double(pow(2, 16)).longValue())) < 0){
+        }else if(bigInteger.compareTo(BigInteger.valueOf(uint16Max)) <= 0){
             return 3;
-        }else if(bigInteger.compareTo(BigInteger.valueOf(
-                new Double(pow(2, 32)).longValue())) < 0){
+        }else if(bigInteger.compareTo(BigInteger.valueOf(uint32Max))<= 0){
             return 5;
-        }else if(bigInteger.compareTo(BigInteger.valueOf(
-                new Double(pow(2, 64)).longValue())) <= 0){
-            // 这里其实是与long的最大值做对比，所以可以等
+        }else if(bigInteger.compareTo(BigInteger.valueOf(uint64Max)) <= 0){
             return 9;
         }else{
             //MIN1.0中，VlInt的size最大为9
@@ -287,6 +287,7 @@ public class VlInt {
 
     /**
      * 将BigInteger转为byte[按照变长无符号整数方式转]
+     *
      * @param bigInteger
      * @return
      */
diff --git a/src/test/java/encoding/TLVTest.java b/src/test/java/encoding/TLVTest.java
index e19ef55..63fb823 100644
--- a/src/test/java/encoding/TLVTest.java
+++ b/src/test/java/encoding/TLVTest.java
@@ -1,6 +1,7 @@
 package encoding;
 
 import org.junit.Test;
+import util.ByteHelper;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
@@ -14,12 +15,69 @@ import static org.junit.Assert.assertTrue;
  */
 public class TLVTest {
     @Test
-    public void testReadVarNumber() throws TLVException {
+    public void testReadVarNumber() throws TLVException, VlIntException {
         byte[] buf=new byte[10];
         // 测试单个字节表示
         buf[0]=(byte)240;
         VlInt res=TLV.readVarNumber(buf,new VlInt(0));
         assertTrue(res.isEqual(240));
-//        assertEquals();
+
+        // 测试两个字节表示
+        VlInt vlInt=new VlInt(241);
+        System.arraycopy(vlInt.getVlIntBytes(),0,buf,0,3);
+        res=TLV.readVarNumber(buf,new VlInt(0));
+        assertTrue(res.isEqual(241));
+
+        // 测试四个字节表示
+        long maxuint32=(long) (Math.pow(2,32)-1);
+        vlInt=new VlInt(maxuint32);
+        System.arraycopy(vlInt.getVlIntBytes(),0,buf,0,5);
+        res=TLV.readVarNumber(buf,new VlInt(0));
+        assertEquals(res.getVlIntValue2Long(),maxuint32);
+
+        // 测试八个字节表示
+        long maxlong=Long.MAX_VALUE;
+        vlInt=new VlInt(maxlong);
+        System.arraycopy(vlInt.getVlIntBytes(),0,buf,0,9);
+        res=TLV.readVarNumber(buf,new VlInt(0));
+        assertTrue(res.isEqual(maxlong));
+
+        // 测试不支持的情况
+        buf[0]=(byte) 244;
+        try {
+            res=TLV.readVarNumber(buf,new VlInt(0));
+        }catch (Exception | Error e){
+            System.out.println(e.getMessage());
+        }
+    }
+
+    @Test
+    public void testReadType() throws TLVException {
+        byte[] buf=new byte[10];
+        // 测试单个字节表示
+        buf[0]=(byte)240;
+        VlInt res=TLV.readType(buf,new VlInt(0));
+        assertTrue(res.isEqual(240));
+
+        // 测试两个字节表示
+        VlInt vlInt=new VlInt(300);
+        System.arraycopy(vlInt.getVlIntBytes(),0,buf,0,3);
+        res=TLV.readType(buf,new VlInt(0));
+        assertTrue(res.isEqual(300));
+    }
+
+    @Test
+    public void testReadNonNegativeInteger() throws TLVException {
+        byte[] buf=new byte[240];
+        buf[0]=(byte)240;
+        System.arraycopy(ByteHelper.uint16ToByteArray(1234),0,buf,1,2);
+        System.arraycopy(ByteHelper.uint32ToByteArray(1234),0,buf,3,4);
+        System.arraycopy(ByteHelper.uint64ToByteArray(1234),0,buf,7,8);
+        long res=TLV.readNonNegativeInteger(buf,1,3);
+        assertEquals(1234,res);
+        res=TLV.readNonNegativeInteger(buf,3,7);
+        assertEquals(1234,res);
+        res=TLV.readNonNegativeInteger(buf,7,15);
+        assertEquals(1234,res);
     }
 }
diff --git a/src/test/java/encoding/VlIntTest.java b/src/test/java/encoding/VlIntTest.java
index fb9c05d..2117736 100644
--- a/src/test/java/encoding/VlIntTest.java
+++ b/src/test/java/encoding/VlIntTest.java
@@ -217,6 +217,18 @@ public class VlIntTest {
         assertEquals(vlInt1.add(a2),sum1);
     }
 
+    @Test
+    public void testSizeOfNumber(){
+        VlInt vlInt=new VlInt(1);
+        assertEquals(vlInt.size(),1);
+        vlInt=new VlInt(VlInt.uint16Max);
+        assertEquals(vlInt.size(),3);
+        vlInt=new VlInt(VlInt.uint32Max);
+        assertEquals(vlInt.size(),5);
+        vlInt=new VlInt(VlInt.uint64Max);
+        assertEquals(vlInt.size(),9);
+    }
+
 //    @Test
 //    public void bigInteger2vlintBytes(){
 //        BigInteger a1 = BigInteger.valueOf(0);