diff --git a/README.md b/README.md
index 8e3ceec..692be60 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,8 @@
 json/yaml/http header/query string 转成struct定义，免去手写struct的烦恼.    
 
 
-## 一、json字符串生成结构体
+## 一、json/yaml/http header/query string 生成结构体
+### 1.1 json字符串生成结构体
 ```go
 import (
     "github.com/antlabs/tostruct/json"
@@ -73,7 +74,7 @@ func main() {
 }
 ```
 
-## 二、http header生成结构体
+### 1.2 http header生成结构体
 ```go
 import (
     "github.com/antlabs/tostruct/header"
@@ -105,7 +106,7 @@ type test struct {
 	*/
 }
 ```
-## 三、查询字符串生成结构体
+### 1.3、查询字符串生成结构体
 ```go
 import (
     "github.com/antlabs/tostruct/url"
@@ -132,7 +133,7 @@ type test struct {
 
 ```
 
-## 四、yaml生成结构体
+### 1.4 yaml生成结构体
 ```go
 import (
     "github.com/antlabs/tostruct/url"
@@ -209,3 +210,39 @@ type F struct {
 */
 }
 ```
+
+## 二、各种配置项函数用法
+### 2.1 option.WithSpecifyType 指定生成类型
+```go
+obj := `
+{
+  "action": "get",
+  "count": 0,
+  "data": {
+    "a123": "delivered"
+  },
+  "duration": 5,
+  "entities": [],
+  "timestamp": 1542601830084,
+  "uri": "http://XXXX/XXXX/XXXX/users/user1/offline_msg_status/123"
+}
+  `
+// 默认对象是转成结构体的，比如这里的data成员，有些接口返回的key是变动的，比如key是用户名value是消息是否投递成功(假装在im系统中)
+// 此类业务就需要转成map[string]string类型，这里就可以用上option.WithSpecifyType
+// 传参的类型是map[string]string， key为json路径，value值是要指定的类型
+all, err := Marshal([]byte(obj), option.WithStructName("reqName"), option.WithTagName("json"), option.WithSpecifyType(map[string]string{
+	".data": "map[string]string",
+}))
+
+// output all
+type reqName struct {
+	Action    string            `json:"action"`
+	Count     int               `json:"count"`
+	Data      map[string]string `json:"data"`
+	Duration  int               `json:"duration"`
+	entities  interface{}       `json:"json:entities"`
+	Timestamp int               `json:"timestamp"`
+	URI       string            `json:"uri"`
+}
+
+```
\ No newline at end of file
diff --git a/json/json.go b/json/json.go
index 015d4b6..76908cd 100644
--- a/json/json.go
+++ b/json/json.go
@@ -88,6 +88,7 @@ const (
 	boolFmt       = "%s %sbool `%s:\"%s\"`"
 	float64Fmt    = "%s %sfloat64 `%s:\"%s\"`"
 	intFmt        = "%s %sint `%s:\"%s\"`"
+	specifytFmt   = "%s %s `%s:\"%s\"`"
 )
 
 func Marshal[T Type](t T, opt ...option.OptionFunc) (b []byte, err error) {
@@ -104,6 +105,7 @@ func newDefault() *JSON {
 		Option: option.Option{Tag: "json", StructName: defStructName, Inline: true}}
 
 }
+
 func new[T Type](t T, opt ...option.OptionFunc) (f *JSON, err error) {
 	var tmp any = t
 	var rv *JSON
@@ -155,7 +157,7 @@ func new[T Type](t T, opt ...option.OptionFunc) (f *JSON, err error) {
 }
 
 func (f *JSON) marshal() (b []byte, err error) {
-	f.marshalValue("", f.obj, false, 0, &f.buf)
+	f.marshalValue("", f.obj, false, 0, &f.buf, "")
 	f.buf.WriteString(endStruct)
 	if !f.Inline {
 		keys := mapex.Keys(f.structBuf)
@@ -170,6 +172,7 @@ func (f *JSON) marshal() (b []byte, err error) {
 	}
 
 	if b, err = format.Source(f.buf.Bytes()); err != nil {
+		fmt.Printf("%s\n", f.buf.String())
 		return nil, err
 	}
 
@@ -193,7 +196,11 @@ func (f *JSON) getStructTypeName(fieldName string) (structTypeName string, buf *
 	}
 }
 
-func (f *JSON) marshalMap(key string, m map[string]interface{}, typePrefix string, depth int, buf *bytes.Buffer) {
+func appendKeyPath(pathKey string, key string) string {
+	return fmt.Sprintf("%s.%s", pathKey, strings.ToLower(key))
+}
+
+func (f *JSON) marshalMap(key string, m map[string]interface{}, typePrefix string, depth int, buf *bytes.Buffer, pathKey string) {
 
 	remaining := len(m)
 
@@ -212,6 +219,7 @@ func (f *JSON) marshalMap(key string, m map[string]interface{}, typePrefix strin
 
 	if len(key) > 0 {
 		if f.Inline {
+			// 如果是内嵌结构体
 			buf.WriteString(fmt.Sprintf(startInlineMap, fieldName, typePrefix))
 		} else {
 			// 生成struct类型名和子结构体可以保存的子buf
@@ -229,7 +237,7 @@ func (f *JSON) marshalMap(key string, m map[string]interface{}, typePrefix strin
 
 		f.writeIndent(buf, depth+1)
 
-		f.marshalValue(key, m[key], false, depth+1, buf)
+		f.marshalValue(key, m[key], false, depth+1, buf, appendKeyPath(pathKey, key))
 
 		f.writeObjSep(buf)
 	}
@@ -245,16 +253,16 @@ func (f *JSON) marshalMap(key string, m map[string]interface{}, typePrefix strin
 	}
 }
 
-func (f *JSON) marshalArray(key string, a []interface{}, depth int, buf *bytes.Buffer) {
+func (f *JSON) marshalArray(key string, a []interface{}, depth int, buf *bytes.Buffer, keyPath string) {
 	if len(a) == 0 {
 		buf.WriteString(fmt.Sprintf("%s interface{} `json:\"json:%s\"`", key, key))
 		return
 	}
 
-	f.marshalValue(key, a[0], true, depth, buf)
+	f.marshalValue(key, a[0], true, depth, buf, keyPath)
 }
 
-func (f *JSON) marshalValue(key string, obj interface{}, fromArray bool, depth int, buf *bytes.Buffer) {
+func (f *JSON) marshalValue(key string, obj interface{}, fromArray bool, depth int, buf *bytes.Buffer, keyPath string) {
 	typePrefix := ""
 	if fromArray {
 		typePrefix = "[]"
@@ -262,6 +270,14 @@ func (f *JSON) marshalValue(key string, obj interface{}, fromArray bool, depth i
 
 	fieldName, tagName := name.GetFieldAndTagName(key)
 
+	if f.TypeMap != nil {
+		fieldType, ok := f.TypeMap[keyPath]
+		if ok {
+			buf.WriteString(fmt.Sprintf(specifytFmt, fieldName, fieldType, f.Tag, tagName))
+			return
+		}
+	}
+
 	tmpFieldName := strings.ToUpper(fieldName)
 	if tab.InitialismsTab[tmpFieldName] {
 		fieldName = tmpFieldName
@@ -269,9 +285,9 @@ func (f *JSON) marshalValue(key string, obj interface{}, fromArray bool, depth i
 
 	switch v := obj.(type) {
 	case map[string]interface{}:
-		f.marshalMap(key, v, typePrefix, depth, buf)
+		f.marshalMap(key, v, typePrefix, depth, buf, keyPath)
 	case []interface{}:
-		f.marshalArray(key, v, depth, buf)
+		f.marshalArray(key, v, depth, buf, keyPath+"[0]")
 	case string:
 		buf.WriteString(fmt.Sprintf(stringFmt, fieldName, typePrefix, f.Tag, tagName))
 	case float64: //json默认解析的数字是float64类型
diff --git a/json/json_empty_test.go b/json/json_empty_test.go
new file mode 100644
index 0000000..f6d0ffc
--- /dev/null
+++ b/json/json_empty_test.go
@@ -0,0 +1,15 @@
+package json
+
+import (
+	"testing"
+
+	"github.com/antlabs/tostruct/option"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEmpty(t *testing.T) {
+	str := []byte("")
+	all, err := Marshal(str, option.WithStructName("empty"), option.WithTagName("json"))
+	assert.Error(t, err)
+	assert.Equal(t, all, []byte(nil))
+}
diff --git a/json/json_test.go b/json/json_test.go
index d8be94c..c747c07 100644
--- a/json/json_test.go
+++ b/json/json_test.go
@@ -170,3 +170,89 @@ func Test_Gen_Obj_JSON6(t *testing.T) {
 	}
 
 }
+
+func Test_Gen_Obj_JSON7(t *testing.T) {
+
+	obj := `
+{
+  "action": "get",
+  "count": 0,
+  "data": {
+    "a123": "delivered"
+  },
+  "duration": 5,
+  "entities": [],
+  "timestamp": 1542601830084,
+  "uri": "http://XXXX/XXXX/XXXX/users/user1/offline_msg_status/123"
+}
+  `
+
+	for _, v := range [][]byte{
+		func() []byte {
+			all, err := Marshal([]byte(obj), option.WithStructName("reqName"), option.WithTagName("json"), option.WithSpecifyType(map[string]string{
+				".data": "map[string]string",
+			}))
+			assert.NoError(t, err)
+			return all
+		}(),
+		func() []byte {
+			all, err := Marshal([]byte(obj), option.WithStructName("reqName"), option.WithTagName("json"), option.WithNotInline(), option.WithSpecifyType(map[string]string{
+				".data": "map[string]string",
+			}))
+			assert.NoError(t, err)
+			return all
+		}(),
+	} {
+
+		all := v
+		fmt.Println(string(all))
+		need, err := os.ReadFile("../testdata/testjson7.0.txt")
+		assert.NoError(t, err)
+		assert.Equal(t, string(bytes.TrimSpace(need)), string(bytes.TrimSpace(all)))
+	}
+
+}
+
+func Test_Gen_Obj_JSON8(t *testing.T) {
+
+	obj := `
+{
+  "action": "get",
+  "count": 0,
+  "data": {
+    "data": {
+      "a123": "delivered"
+    }
+  },
+  "duration": 5,
+  "entities": [],
+  "timestamp": 1542601830084,
+  "uri": "http://XXXX/XXXX/XXXX/users/user1/offline_msg_status/123"
+}
+  `
+
+	for k, v := range [][]byte{
+		func() []byte {
+			all, err := Marshal([]byte(obj), option.WithStructName("reqName"), option.WithTagName("json"), option.WithSpecifyType(map[string]string{
+				".data.data": "map[string]string",
+			}))
+			assert.NoError(t, err)
+			return all
+		}(),
+		func() []byte {
+			all, err := Marshal([]byte(obj), option.WithStructName("reqName"), option.WithTagName("json"), option.WithNotInline(), option.WithSpecifyType(map[string]string{
+				".data.data": "map[string]string",
+			}))
+			assert.NoError(t, err)
+			return all
+		}(),
+	} {
+
+		all := v
+		fmt.Println(string(all))
+		need, err := os.ReadFile(fmt.Sprintf("../testdata/testjson8.%d.txt", k))
+		assert.NoError(t, err)
+		assert.Equal(t, string(bytes.TrimSpace(need)), string(bytes.TrimSpace(all)))
+	}
+
+}
diff --git a/option/option.go b/option/option.go
index 13c15d0..5d6a8d2 100644
--- a/option/option.go
+++ b/option/option.go
@@ -8,6 +8,7 @@ type Option struct {
 	Inline     bool
 	Tag        string
 	StructName string
+	TypeMap    map[string]string
 }
 
 // 控制生成的结构体是否内联
@@ -42,3 +43,22 @@ func WithStructName(name string) OptionFunc {
 		c.StructName = name
 	}
 }
+
+// 指定类型, datal默认转成struct， 这里直接指定生成map[string]string类型
+// {
+//
+//		"data" : {
+//		  "user1": "111"
+//		}
+//	}
+//
+//	WithSpecifyType(map[string]string{
+//	   ".data": "map[string]string"
+//	})
+//
+// 目录只支持json/yaml
+func WithSpecifyType(typeMap map[string]string) OptionFunc {
+	return func(c *Option) {
+		c.TypeMap = typeMap
+	}
+}
diff --git a/testdata/testjson7.0.txt b/testdata/testjson7.0.txt
new file mode 100644
index 0000000..e8a3abf
--- /dev/null
+++ b/testdata/testjson7.0.txt
@@ -0,0 +1,9 @@
+type reqName struct {
+	Action    string            `json:"action"`
+	Count     int               `json:"count"`
+	Data      map[string]string `json:"data"`
+	Duration  int               `json:"duration"`
+	entities  interface{}       `json:"json:entities"`
+	Timestamp int               `json:"timestamp"`
+	URI       string            `json:"uri"`
+}
diff --git a/testdata/testjson8.0.txt b/testdata/testjson8.0.txt
new file mode 100644
index 0000000..85f5ecf
--- /dev/null
+++ b/testdata/testjson8.0.txt
@@ -0,0 +1,11 @@
+type reqName struct {
+	Action string `json:"action"`
+	Count  int    `json:"count"`
+	Data   struct {
+		Data map[string]string `json:"data"`
+	} `json:"data"`
+	Duration  int         `json:"duration"`
+	entities  interface{} `json:"json:entities"`
+	Timestamp int         `json:"timestamp"`
+	URI       string      `json:"uri"`
+}
diff --git a/testdata/testjson8.1.txt b/testdata/testjson8.1.txt
new file mode 100644
index 0000000..be68375
--- /dev/null
+++ b/testdata/testjson8.1.txt
@@ -0,0 +1,13 @@
+type reqName struct {
+	Action    string      `json:"action"`
+	Count     int         `json:"count"`
+	Data      Data        `json:"data"`
+	Duration  int         `json:"duration"`
+	entities  interface{} `json:"json:entities"`
+	Timestamp int         `json:"timestamp"`
+	URI       string      `json:"uri"`
+}
+
+type Data struct {
+	Data map[string]string `json:"data"`
+}