diff --git a/ast/iterator_test.go b/ast/iterator_test.go
index 34eee3c8c..437f56fa2 100644
--- a/ast/iterator_test.go
+++ b/ast/iterator_test.go
@@ -231,7 +231,7 @@ func TestExist(t *testing.T) {
         if path.Key != nil && *path.Key == "a" {
             t.Fatal()
         }
-        if path.Index == 1 {
+        if path.Index == 0 {
             if *path.Key != "b" {
                 t.Fatal()
             }
@@ -247,7 +247,7 @@ func TestExist(t *testing.T) {
             })
         }
 
-        if path.Index == 2 {
+        if path.Index == 1 {
             if *path.Key != "c" {
                 t.Fatal()
             }
diff --git a/ast/node.go b/ast/node.go
index 7818ef4da..a3273d396 100644
--- a/ast/node.go
+++ b/ast/node.go
@@ -573,13 +573,16 @@ func (self *Node) Unset(key string) (bool, error) {
     if err := self.should(types.V_OBJECT, "an object"); err != nil {
         return false, err
     }
+    // NOTICE: must get acurate length before deduct
+    if err := self.skipAllKey(); err != nil {
+        return false, err
+    }
     p, i := self.skipKey(key)
     if !p.Exists() {
         return false, nil
     } else if err := p.Check(); err != nil {
         return false, err
     }
-    
     self.removePair(i)
     return true, nil
 }
@@ -619,16 +622,21 @@ func (self *Node) SetAnyByIndex(index int, val interface{}) (bool, error) {
 // UnsetByIndex remove the node of given index
 // WARN: After conducting `UnsetXX()`, the node's length WON'T change
 func (self *Node) UnsetByIndex(index int) (bool, error) {
-    if err := self.Check(); err != nil {
+    if err := self.checkRaw(); err != nil {
         return false, err
     }
 
     var p *Node
     it := self.itype()
+
     if it == types.V_ARRAY {
-        p = self.Index(index)
+        if err := self.skipAllIndex(); err != nil {
+            return false, err
+        }    
+        p = self.skipIndex(index)
+
     } else if it == types.V_OBJECT {
-        if err := self.checkRaw(); err != nil {
+        if err := self.skipAllKey(); err != nil {
             return false, err
         }
         pr := self.skipIndexPair(index)
@@ -636,6 +644,7 @@ func (self *Node) UnsetByIndex(index int) (bool, error) {
            return false, ErrNotExist
         }
         p = &pr.Value
+
     } else {
         return false, ErrUnsupportType
     }
diff --git a/ast/node_test.go b/ast/node_test.go
index c4624d71c..b330a6798 100644
--- a/ast/node_test.go
+++ b/ast/node_test.go
@@ -780,7 +780,7 @@ func TestUnset(t *testing.T) {
     if !entities.Exists() || entities.Check() != nil {
         t.Fatal(entities.Check().Error())
     }
-    exist, err := entities.Unset("urls") // NOTICE: Unset() won't change node.Len() here
+    exist, err := entities.Unset("urls") 
     if !exist || err != nil {
         t.Fatal()
     }
@@ -788,7 +788,7 @@ func TestUnset(t *testing.T) {
     if e.Exists() {
         t.Fatal()
     }
-    if entities.len() != 3 { 
+    if entities.len() != 2 { 
         t.Fatal(entities.len())
     }
 
@@ -828,14 +828,8 @@ func TestUnset(t *testing.T) {
     require.Equal(t, 
 `{"hashtags":[{"text":"freebandnames","indices":[20,34]}],"user_mentions":[],"urls":"a"}`, buf.String())
 
-    exist, err = entities.UnsetByIndex(entities.len()-1)
-    if !exist || err != nil {
-        t.Fatal()
-    }
-    e = entities.Get("urls")
-    if e.Exists() {
-        t.Fatal()
-    }
+    // reload entities
+    *entities = NewRaw(string(out))
 
     hashtags := entities.Get("hashtags").Index(0)
     hashtags.Set("text2", newRawNode(`{}`, types.V_OBJECT))
@@ -851,21 +845,35 @@ func TestUnset(t *testing.T) {
         t.Fatal()
     }
 
+    entities.Load()
+    exist, err = entities.UnsetByIndex(entities.len()-1)
+    if !exist || err != nil {
+        t.Fatal()
+    }
+    if entities.len() != 2 { 
+        t.Fatal(entities.len())
+    }
+    e = entities.Index(entities.len())
+    if e.Exists() {
+        t.Fatal()
+    }
+    
+
     ums := entities.Get("user_mentions")
     ums.Add(NewNull())
-    ums.Add(NewBool(true))
     ums.Add(NewBool(false))
+    ums.Add(NewBool(true))
     if ums.len() != 3 {
         t.Fatal()
     }
-    exist, err = ums.UnsetByIndex(2)
+    exist, err = ums.UnsetByIndex(1)
     if !exist || err != nil {
         t.Fatal()
     }
-
+    require.Equal(t, 2, ums.len())
     umses, err := ums.Interface()
     require.NoError(t, err)
-    require.Equal(t, []interface{}{interface{}(nil), true},umses)
+    require.Equal(t, []interface{}{interface{}(nil), true}, umses)
 
     v1, _ := ums.Index(0).Interface()
     v2, _ := ums.Index(1).Interface() // NOTICE: unseted index 1 still can be find here