diff --git a/alipay/service_api.go b/alipay/service_api.go
index 2d596c0f..2dc63ff4 100644
--- a/alipay/service_api.go
+++ b/alipay/service_api.go
@@ -526,8 +526,9 @@ func DecryptOpenDataToBodyMap(encryptedData, secretKey string) (bm gopay.BodyMap
 //    PrivateKey：应用私钥
 //    grantType：值为 authorization_code 时，代表用code换取；值为 refresh_token 时，代表用refresh_token换取，传空默认code换取
 //    codeOrToken：支付宝授权码或refresh_token
+//    signType：签名方式 RSA 或 RSA2，默认 RSA2
 //    文档：https://docs.open.alipay.com/api_9/alipay.system.oauth.token
-func SystemOauthToken(appId, privateKey, grantType, codeOrToken string) (rsp *SystemOauthTokenResponse, err error) {
+func SystemOauthToken(appId, privateKey, grantType, codeOrToken, signType string) (rsp *SystemOauthTokenResponse, err error) {
 	var bs []byte
 	bm := make(gopay.BodyMap)
 	if "authorization_code" == grantType {
@@ -540,7 +541,7 @@ func SystemOauthToken(appId, privateKey, grantType, codeOrToken string) (rsp *Sy
 		bm.Set("grant_type", "authorization_code")
 		bm.Set("code", codeOrToken)
 	}
-	if bs, err = systemOauthToken(appId, privateKey, bm, "alipay.system.oauth.token", true, "RSA2"); err != nil {
+	if bs, err = systemOauthToken(appId, privateKey, bm, "alipay.system.oauth.token", true, signType); err != nil {
 		return
 	}
 	rsp = new(SystemOauthTokenResponse)
@@ -559,6 +560,11 @@ func systemOauthToken(appId, privateKey string, body gopay.BodyMap, method strin
 	body.Set("method", method)
 	body.Set("format", "JSON")
 	body.Set("charset", "utf-8")
+	if signType == gopay.NULL {
+		body.Set("sign_type", "RSA2")
+	} else {
+		body.Set("sign_type", signType)
+	}
 	body.Set("sign_type", signType)
 	body.Set("timestamp", time.Now().Format(gopay.TimeLayout))
 	body.Set("version", "1.0")
diff --git a/examples/alipay/alipay_ServiceApi.go b/examples/alipay/alipay_ServiceApi.go
index e0e090c4..9949ad9b 100644
--- a/examples/alipay/alipay_ServiceApi.go
+++ b/examples/alipay/alipay_ServiceApi.go
@@ -24,7 +24,7 @@ func FormatPublicKey() {
 
 func SystemOauthToken2() {
 	privateKey := "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"
-	rsp, err := alipay.SystemOauthToken("2016091200494382", privateKey, "", "06e8961891d647c0ac99bb1cebe7SE69")
+	rsp, err := alipay.SystemOauthToken("2016091200494382", privateKey, "", "06e8961891d647c0ac99bb1cebe7SE69", "RSA2")
 	if err != nil {
 		fmt.Println("SystemOauthToken:", err)
 		return
diff --git a/release_note.txt b/release_note.txt
index 5e5be664..12aa1964 100644
--- a/release_note.txt
+++ b/release_note.txt
@@ -1,3 +1,8 @@
+版本号：Release 1.5.3
+发布时间：2020/02/19 11:32
+修改记录：
+   (1) 支付宝：修改公共方法：SystemOauthToken()，添加参数 signType
+
 版本号：Release 1.5.2
 发布时间：2020/02/14 13:32
 修改记录：