diff --git a/weixin4j-base/src/main/java/com/foxinmy/weixin4j/util/MapUtil.java b/weixin4j-base/src/main/java/com/foxinmy/weixin4j/util/MapUtil.java
index 505c8f57..f6ef2254 100644
--- a/weixin4j-base/src/main/java/com/foxinmy/weixin4j/util/MapUtil.java
+++ b/weixin4j-base/src/main/java/com/foxinmy/weixin4j/util/MapUtil.java
@@ -71,6 +71,7 @@ public class MapUtil {
 	 */
 	public static String toJoinString(Map<String, String> map, boolean encoder,
 			boolean lowerCase) {
+		map.remove("sign");
 		StringBuilder sb = new StringBuilder();
 		Set<Map.Entry<String, String>> set = map.entrySet();
 		try {
diff --git a/weixin4j-mp/src/test/java/com/foxinmy/weixin4j/mp/test/XmlstreamTest.java b/weixin4j-mp/src/test/java/com/foxinmy/weixin4j/mp/test/XmlstreamTest.java
index 030d409c..64ba7fab 100644
--- a/weixin4j-mp/src/test/java/com/foxinmy/weixin4j/mp/test/XmlstreamTest.java
+++ b/weixin4j-mp/src/test/java/com/foxinmy/weixin4j/mp/test/XmlstreamTest.java
@@ -113,7 +113,7 @@ public class XmlstreamTest {
 		String sign = refundRecord.getSign();
 		refundRecord.setSign(null);
 		String validSign = PayUtil.paysignMd5(refundRecord,
-				"GATFzDwbQdbbci3QEQxX2rUBvwTrsMiZ");
+				"paysignkey");
 		System.err.println("sign=" + sign + ",validSign=" + validSign);
 		System.err.println(ListsuffixResultSerializer.serializeToXML(refundRecord));
 	}