diff --git a/lib/addax-rdbms/src/main/java/com/wgzhao/addax/rdbms/writer/util/WriterUtil.java b/lib/addax-rdbms/src/main/java/com/wgzhao/addax/rdbms/writer/util/WriterUtil.java
index 9a17de7c7..0481b3776 100644
--- a/lib/addax-rdbms/src/main/java/com/wgzhao/addax/rdbms/writer/util/WriterUtil.java
+++ b/lib/addax-rdbms/src/main/java/com/wgzhao/addax/rdbms/writer/util/WriterUtil.java
@@ -177,7 +177,7 @@ else if (dataBaseType == DataBaseType.SQLServer) {
 
     private static String doPostgresqlUpdate(String writeMode, List<String> columnHolders)
     {
-        String conflict = writeMode.replace("update", "");
+        String conflict = writeMode.replaceFirst("update", "");
         StringBuilder sb = new StringBuilder();
         sb.append(" ON CONFLICT ");
         sb.append(conflict);