diff --git a/mutable_xobject.go b/mutable_xobject.go
index 101ed7e..4fde087 100644
--- a/mutable_xobject.go
+++ b/mutable_xobject.go
@@ -6,11 +6,15 @@ type MutableXObject struct {
 
 func NewMxoArray() *MutableXObject {
 	p := new(MutableXObject)
+	p.XObject._type = XOT_ARRAY
+	p.XObject._val = make([]*XObject, 10)
 	return p
 }
 
 func NewMxoObject() *MutableXObject {
 	p := new(MutableXObject)
+	p.XObject._type = XOT_OBJECT
+	p.XObject._val = make(map[string]*XObject)
 	return p
 }
 
@@ -23,8 +27,8 @@ func (this *MutableXObject) PushXObject(val *XObject) *MutableXObject{
 	if this.XObject.GetType() != XOT_ARRAY {
 		panic("MutableXObject.PushXvalue type error")
 	}
-	array := this.XObject._val.(*[]*XObject)
-	this.XObject._val = append(*array, val)
+	array := this.XObject._val.([]*XObject)
+	this.XObject._val = append(array, val)
 	return this
 }
 
@@ -37,8 +41,8 @@ func (this *MutableXObject) SetXObject(key string, val *XObject) *MutableXObject
 	if this.XObject.GetType() != XOT_OBJECT {
 		panic("MutableXObject.PushXvalue type error")
 	}
-	kvObj := this.XObject._val.(*(map[string]*XObject))
-	(*kvObj)[key] = val
+	kvObj := this.XObject._val.(map[string]*XObject)
+	kvObj[key] = val
 	return this
 }
 
diff --git a/xobject.go b/xobject.go
index e8ec51f..f9ae64c 100644
--- a/xobject.go
+++ b/xobject.go
@@ -24,22 +24,22 @@ func NewXoFromJsonStr(jsonStr string) *XObject {
 	}
 }
 
-func (this *XObject) Size(key interface{}) int {
+func (this *XObject) Size() int {
 	if (this._type == XOT_ARRAY) {
-		array := this._val.(*[]*XObject)
-		return len(*array)
+		array := this._val.([]*XObject)
+		return len(array)
 	} else {
 		panic("XObject.Size type error")
 		return 0
 	}
 }
 
-func (this *XObject) Reset() {
+func (this *XObject) reset() {
 	this._type = XOT_SIMPLE
-	this._val = nil
+	this._val = NewXUndefined()
 }
 
-func (this *XObject) GetType() int8{
+func (this *XObject) GetType() int8 {
 	return this._type
 }
 
@@ -73,8 +73,8 @@ func (this *XObject) At(key string) *XObject {
 
 func (this *XObject) Index(index int32) *XObject {
 	if (this._type == XOT_ARRAY) {
-		array := this._val.(*[]*XObject)
-		return (*array)[index]
+		array := this._val.([]*XObject)
+		return array[index]
 	} else {
 		panic("XObject.At type error")
 		return nil
@@ -107,6 +107,7 @@ func (this *XObject) readFromJsonString(data string) bool {
 		}
 		this._type = XOT_OBJECT
 		this._val = kvObj
+		return true
 	} else if jsonType == JSON_ARRAY {
 		var rawJson []interface{}
 		err := json.Unmarshal([]byte(data), &rawJson)
@@ -120,6 +121,7 @@ func (this *XObject) readFromJsonString(data string) bool {
 			xobj := new(XObject).fromInterface(val)
 			arrObj[index] = xobj
 		}
+		return true
 	}
 	return false
 }
@@ -135,9 +137,9 @@ func (this *XObject) ToJsonStr() string {
 
 func (this *XObject) ToInterface() interface{} {
 	if this._type == XOT_ARRAY {
-		array := this._val.(*[]*XObject)
-		arrObj := make([]interface{}, len(*array))
-		for index, val := range *array {
+		array := this._val.([]*XObject)
+		arrObj := make([]interface{}, len(array))
+		for index, val := range array {
 			arrObj[index] = val.ToInterface()
 		}
 		return arrObj
@@ -152,12 +154,27 @@ func (this *XObject) ToInterface() interface{} {
 	return this.AsXValue().ToJsonInterface()
 }
 
-func (this *XObject) fromInterface(val interface{}) *XObject {
-	if this._type != XOT_SIMPLE {
-		panic("XObject.fromInterface type error1")
-	}
-	if !this.AsXValue().TryFromInterface(val) {
-		panic("XObject.fromInterface type error2")
+func (this *XObject) fromInterface(iVal interface{}) *XObject {
+	if array, ok := iVal.([]interface{}); ok {
+		arrObj := make([]*XObject, len(array))
+		for index, val := range array {
+			arrObj[index] = new(XObject).fromInterface(val)
+		}
+		this._type = XOT_ARRAY
+		this._val = arrObj
+	} else if object, ok := iVal.(map[string]interface{}); ok {
+		kvObj := make(map[string]*XObject)
+		for key, val := range object {
+			kvObj[key] = new(XObject).fromInterface(val)
+		}
+		this._type = XOT_OBJECT
+		this._val = kvObj
+	} else {
+		this._type = XOT_SIMPLE
+		this._val = NewXUndefined()
+		if !this.AsXValue().TryFromInterface(iVal) {
+			panic("XObject.fromInterface type error2")
+		}
 	}
 	return this
 }