diff --git a/config/reader.go b/config/reader.go
index 179716a..4af0215 100644
--- a/config/reader.go
+++ b/config/reader.go
@@ -44,8 +44,8 @@ func (c *FileConfig) parse(confName string) (err error) {
 	return err
 }
 
-// NewConfig create from file.
-func NewConfig(confName string) (ConfigInterface, error) {
+// ReadConfig create from file.
+func ReadConfig(confName string) (*FileConfig, error) {
 	c := &FileConfig{}
 	err := c.parse(confName)
 	return c, err
diff --git a/config/reader_test.go b/config/reader_test.go
index d0e4bf1..075d73b 100644
--- a/config/reader_test.go
+++ b/config/reader_test.go
@@ -3,21 +3,21 @@ package config
 import "testing"
 
 func TestNewConfig(t *testing.T) {
-	config, err := NewConfig("../examples/token_conf.yaml")
+	config, err := ReadConfig("../examples/token_conf.yaml")
 	if err != nil {
 		t.Errorf("read error: %v", err)
 	}
-	tokenConfig := config.(*FileConfig).TokenConfig
+	tokenConfig := config.TokenConfig
 
 	t.Log(tokenConfig)
 }
 
 func TestNewIniConfig(t *testing.T) {
-	config, err := NewConfig("../examples/token_conf.ini")
+	config, err := ReadConfig("../examples/token_conf.ini")
 	if err != nil {
 		t.Errorf("read error: %v", err)
 	}
-	tokenConfig := config.(*FileConfig).TokenConfig
+	tokenConfig := config.TokenConfig
 
 	t.Log(tokenConfig)
 }
diff --git a/enforcer.go b/enforcer.go
index f1e75c6..450d174 100644
--- a/enforcer.go
+++ b/enforcer.go
@@ -71,11 +71,11 @@ func InitWithFile(conf string, adapter persist.Adapter) (*Enforcer, error) {
 	if conf == "" || adapter == nil {
 		return nil, errors.New("InitWithFile() failed: parameters cannot be nil")
 	}
-	newConfig, err := config.NewConfig(conf)
+	newConfig, err := config.ReadConfig(conf)
 	if err != nil {
 		return nil, err
 	}
-	enforcer, err := InitWithConfig(newConfig.(*config.FileConfig).TokenConfig, adapter)
+	enforcer, err := InitWithConfig(newConfig.TokenConfig, adapter)
 	enforcer.conf = conf
 	return enforcer, err
 }