diff --git a/databendwriter/doc/databendwriter-CN.md b/databendwriter/doc/databendwriter-CN.md
index d6a8f1f3..5b26ed7e 100644
--- a/databendwriter/doc/databendwriter-CN.md
+++ b/databendwriter/doc/databendwriter-CN.md
@@ -79,6 +79,8 @@ create table if not exsits datax.sample1(a string, b int64, c date, d timestamp,
         "writer": {
           "name": "databendwriter",
           "parameter": {
+            "writeMode": "replace", 
+            "onConflictColumn": ["id"],
             "username": "databend",
             "password": "databend",
             "column": ["a", "b", "c", "d", "e", "f", "g"],
@@ -149,6 +151,16 @@ create table if not exsits datax.sample1(a string, b int64, c date, d timestamp,
     * 必选: 否
     * 默认值: 无
     * 示例: ["select count(*) from datax.sample1"]
+* writeMode
+    * 描述：写入模式，支持 insert 和 replace 两种模式，默认为 insert。若为 replace，务必填写 onConflictColumn 参数
+    * 必选：否
+    * 默认值：insert
+    * 示例："replace"
+* onConflictColumn
+    * 描述：on conflict 字段，指定 writeMode 为 replace 后，需要此参数
+    * 必选：否
+    * 默认值：无
+    * 示例：["id","user"]
 
 ### 3.3 类型转化
 DataX中的数据类型可以转换为databend中的相应数据类型。下表显示了两种类型之间的对应关系。
diff --git a/databendwriter/doc/databendwriter.md b/databendwriter/doc/databendwriter.md
index 0b57bf13..1712504f 100644
--- a/databendwriter/doc/databendwriter.md
+++ b/databendwriter/doc/databendwriter.md
@@ -142,6 +142,16 @@ create table if not exsits datax.sample1(a string, b int64, c date, d timestamp,
   * Description: A list of SQL statements that will be executed after the write operation.
   * Required: no
   * Default: none
+* writeMode
+  * Description：The write mode, support `insert` and `replace` two mode.
+  * Required：否
+  * Default：insert
+  * Example："replace"
+* onConflictColumn
+  * Description：On conflict fields list.
+  * Required：否
+  * Default：无
+  * Example：["id","user"]
 
 ### 3.3 Type Convert
 Data types in datax can be converted to the corresponding data types in databend. The following table shows the correspondence between the two types.
diff --git a/databendwriter/src/main/java/com/alibaba/datax/plugin/writer/databendwriter/util/DatabendWriterUtil.java b/databendwriter/src/main/java/com/alibaba/datax/plugin/writer/databendwriter/util/DatabendWriterUtil.java
index 10a3e09c..00a7c62a 100644
--- a/databendwriter/src/main/java/com/alibaba/datax/plugin/writer/databendwriter/util/DatabendWriterUtil.java
+++ b/databendwriter/src/main/java/com/alibaba/datax/plugin/writer/databendwriter/util/DatabendWriterUtil.java
@@ -19,7 +19,7 @@ public final class DatabendWriterUtil {
 
     public static void dealWriteMode(Configuration originalConfig) {
         List<String> columns = originalConfig.getList(Key.COLUMN, String.class);
-        String valueHolders = "?";
+        List<String> onConflictColumns = originalConfig.getList(Key.ONCONFLICT_COLUMN, String.class);
         StringBuilder writeDataSqlTemplate = new StringBuilder();
 
         String jdbcUrl = originalConfig.getString(String.format("%s[0].%s",
@@ -28,9 +28,13 @@ public final class DatabendWriterUtil {
         String writeMode = originalConfig.getString(Key.WRITE_MODE, "INSERT");
         LOG.info("write mode is {}", writeMode);
         if (writeMode.toLowerCase().contains("replace")) {
+            if (onConflictColumns == null || onConflictColumns.size() == 0) {
+                LOG.error("Replace mode must has onConflictColumn conf");
+                return;
+            }
             // for databend if you want to use replace mode, the writeMode should be:  "writeMode": "replace (userid)"
             writeDataSqlTemplate.append("REPLACE INTO %s (")
-                    .append(StringUtils.join(columns, ",")).append(") ").append(onConFlictDoString(writeMode))
+                    .append(StringUtils.join(columns, ",")).append(") ").append(onConFlictDoString(onConflictColumns))
                     .append(" VALUES");
 
             LOG.info("Replace data [\n{}\n], which jdbcUrl like:[{}]", writeDataSqlTemplate, jdbcUrl);
@@ -51,11 +55,9 @@ public final class DatabendWriterUtil {
         }
     }
 
-    public static String onConFlictDoString(String conflict) {
-        conflict = conflict.replace("replace", "");
-        StringBuilder sb = new StringBuilder();
-        sb.append(" ON ");
-        sb.append(conflict);
-        return sb.toString();
+    public static String onConFlictDoString(List<String> conflictColumns) {
+        return " ON " +
+                "(" +
+                StringUtils.join(conflictColumns, ",") + ") ";
     }
 }
diff --git a/plugin-rdbms-util/src/main/java/com/alibaba/datax/plugin/rdbms/writer/Key.java b/plugin-rdbms-util/src/main/java/com/alibaba/datax/plugin/rdbms/writer/Key.java
index 25a2ab52..3c282d5d 100755
--- a/plugin-rdbms-util/src/main/java/com/alibaba/datax/plugin/rdbms/writer/Key.java
+++ b/plugin-rdbms-util/src/main/java/com/alibaba/datax/plugin/rdbms/writer/Key.java
@@ -11,6 +11,8 @@ public final class Key {
 
     public final static String COLUMN = "column";
 
+    public final static String ONCONFLICT_COLUMN = "onConflictColumn";
+
     //可选值为：insert,replace，默认为 insert （mysql 支持，oracle 没用 replace 机制，只能 insert,oracle 可以不暴露这个参数）
     public final static String WRITE_MODE = "writeMode";