diff --git a/object/token.go b/object/token.go
index 986b40e75743..6fbe840e4320 100644
--- a/object/token.go
+++ b/object/token.go
@@ -144,6 +144,48 @@ func getTokenByCode(code string) (*Token, error) {
 	return nil, nil
 }
 
+func GetTokenByAccessToken(accessToken string) (*Token, error) {
+	token := Token{AccessTokenHash: getTokenHash(accessToken)}
+	existed, err := ormer.Engine.Get(&token)
+	if err != nil {
+		return nil, err
+	}
+
+	if !existed {
+		token = Token{AccessToken: accessToken}
+		existed, err = ormer.Engine.Get(&token)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if !existed {
+		return nil, nil
+	}
+	return &token, nil
+}
+
+func GetTokenByRefreshToken(refreshToken string) (*Token, error) {
+	token := Token{RefreshTokenHash: getTokenHash(refreshToken)}
+	existed, err := ormer.Engine.Get(&token)
+	if err != nil {
+		return nil, err
+	}
+
+	if !existed {
+		token = Token{RefreshToken: refreshToken}
+		existed, err = ormer.Engine.Get(&token)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if !existed {
+		return nil, nil
+	}
+	return &token, nil
+}
+
 func updateUsedByCode(token *Token) bool {
 	affected, err := ormer.Engine.Where("code=?", token.Code).Cols("code_is_used").Update(token)
 	if err != nil {
@@ -219,18 +261,16 @@ func DeleteToken(token *Token) (bool, error) {
 }
 
 func ExpireTokenByAccessToken(accessToken string) (bool, *Application, *Token, error) {
-	token := Token{AccessTokenHash: getTokenHash(accessToken)}
-	existed, err := ormer.Engine.Get(&token)
+	token, err := GetTokenByAccessToken(accessToken)
 	if err != nil {
 		return false, nil, nil, err
 	}
-
-	if !existed {
+	if token == nil {
 		return false, nil, nil, nil
 	}
 
 	token.ExpiresIn = 0
-	affected, err := ormer.Engine.ID(core.PK{token.Owner, token.Name}).Cols("expires_in").Update(&token)
+	affected, err := ormer.Engine.ID(core.PK{token.Owner, token.Name}).Cols("expires_in").Update(token)
 	if err != nil {
 		return false, nil, nil, err
 	}
@@ -240,22 +280,7 @@ func ExpireTokenByAccessToken(accessToken string) (bool, *Application, *Token, e
 		return false, nil, nil, err
 	}
 
-	return affected != 0, application, &token, nil
-}
-
-func GetTokenByAccessToken(accessToken string) (*Token, error) {
-	// Check if the accessToken is in the database
-	token := Token{AccessTokenHash: getTokenHash(accessToken)}
-	existed, err := ormer.Engine.Get(&token)
-	if err != nil {
-		return nil, err
-	}
-
-	if !existed {
-		return nil, nil
-	}
-
-	return &token, nil
+	return affected != 0, application, token, nil
 }
 
 func GetTokenByTokenAndApplication(token string, application string) (*Token, error) {
@@ -457,16 +482,17 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 			ErrorDescription: "client_id is invalid",
 		}, nil
 	}
+
 	if clientSecret != "" && application.ClientSecret != clientSecret {
 		return &TokenError{
 			Error:            InvalidClient,
 			ErrorDescription: "client_secret is invalid",
 		}, nil
 	}
+
 	// check whether the refresh token is valid, and has not expired.
-	token := Token{RefreshTokenHash: getTokenHash(refreshToken)}
-	existed, err := ormer.Engine.Get(&token)
-	if err != nil || !existed {
+	token, err := GetTokenByRefreshToken(refreshToken)
+	if err != nil || token == nil {
 		return &TokenError{
 			Error:            InvalidGrant,
 			ErrorDescription: "refresh token is invalid, expired or revoked",
@@ -477,6 +503,12 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 	if err != nil {
 		return nil, err
 	}
+	if cert == nil {
+		return &TokenError{
+			Error:            InvalidGrant,
+			ErrorDescription: fmt.Sprintf("cert: %s cannot be found", application.Cert),
+		}, nil
+	}
 
 	_, err = ParseJwtToken(refreshToken, cert)
 	if err != nil {
@@ -485,6 +517,7 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 			ErrorDescription: fmt.Sprintf("parse refresh token error: %s", err.Error()),
 		}, nil
 	}
+
 	// generate a new token
 	user, err := getUser(application.Organization, token.User)
 	if err != nil {
@@ -502,6 +535,7 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 	if err != nil {
 		return nil, err
 	}
+
 	newAccessToken, newRefreshToken, tokenName, err := generateJwtToken(application, user, "", scope, host)
 	if err != nil {
 		return &TokenError{
@@ -529,7 +563,7 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 		return nil, err
 	}
 
-	_, err = DeleteToken(&token)
+	_, err = DeleteToken(token)
 	if err != nil {
 		return nil, err
 	}
@@ -542,7 +576,6 @@ func RefreshToken(grantType string, refreshToken string, scope string, clientId
 		ExpiresIn:    newToken.ExpiresIn,
 		Scope:        newToken.Scope,
 	}
-
 	return tokenWrapper, nil
 }