diff --git a/platformapi/wxpayapi/wxpayapi.go b/platformapi/wxpayapi/wxpayapi.go
index fd867cff..09dd7989 100644
--- a/platformapi/wxpayapi/wxpayapi.go
+++ b/platformapi/wxpayapi/wxpayapi.go
@@ -411,13 +411,13 @@ func (a *API) signParam(signType string, params map[string]interface{}) (sig str
 	valueList = append(valueList, fmt.Sprintf("key=%s", a.appKey))
 	sig = strings.Join(valueList, "&")
 	var binSig []byte
-	if signType == sigTypeMd5 {
-		binSig2 := md5.Sum([]byte(sig))
-		binSig = binSig2[:]
-	} else if signType == sigTypeSha256 {
+	if signType == sigTypeSha256 {
 		mac := hmac.New(sha256.New, []byte(a.appKey))
 		mac.Write([]byte(sig))
 		binSig = mac.Sum(nil)
+	} else {
+		binSig2 := md5.Sum([]byte(sig))
+		binSig = binSig2[:]
 	}
 	sig = fmt.Sprintf("%X", binSig)
 	// baseapi.SugarLogger.Debug(sig)