diff --git a/config/src/main/java/com/alibaba/nacos/config/server/enums/OperationType.java b/config/src/main/java/com/alibaba/nacos/config/server/enums/OperationType.java
index e0d8d28158..791c41ffdf 100644
--- a/config/src/main/java/com/alibaba/nacos/config/server/enums/OperationType.java
+++ b/config/src/main/java/com/alibaba/nacos/config/server/enums/OperationType.java
@@ -24,24 +24,19 @@
 public enum OperationType {
 
     /**
-     * Insert
+     * Insert.
      */
     INSERT("I"),
 
     /**
-     * Update
+     * Update.
      */
     UPDATE("U"),
 
     /**
-     * Delete
+     * Delete.
      */
-    DELETE("D"),
-
-    /**
-     * Select
-     */
-    SELECT("S");
+    DELETE("D");
 
     /**
      * operation type value.
@@ -52,7 +47,7 @@ public enum OperationType {
         this.value = value;
     }
 
-    public void setValue(String value){
+    public void setValue(String value) {
         this.value = value;
     }
 
@@ -60,4 +55,4 @@ public String getValue() {
         return this.value;
     }
 
-}
+}
\ No newline at end of file
diff --git a/config/src/test/java/com/alibaba/nacos/config/server/service/HistoryServiceTest.java b/config/src/test/java/com/alibaba/nacos/config/server/service/HistoryServiceTest.java
index 700bb32336..876bf99c73 100644
--- a/config/src/test/java/com/alibaba/nacos/config/server/service/HistoryServiceTest.java
+++ b/config/src/test/java/com/alibaba/nacos/config/server/service/HistoryServiceTest.java
@@ -16,6 +16,7 @@
 
 package com.alibaba.nacos.config.server.service;
 
+import com.alibaba.nacos.config.server.enums.OperationType;
 import com.alibaba.nacos.config.server.model.ConfigHistoryInfo;
 import com.alibaba.nacos.config.server.model.ConfigHistoryInfoPair;
 import com.alibaba.nacos.config.server.model.ConfigInfoWrapper;
@@ -58,7 +59,7 @@ class HistoryServiceTest {
 
     private static final String TEST_UPDATED_CONTENT = "test config updated";
 
-    private static final String TEST_OP_INSERT = "U";
+    private static final String TEST_OP_TYPE = OperationType.UPDATE.getValue();
 
     private static final String TEST_MD5 = "77963b7a931377ad4ab5ad6a9cd718aa";
 
@@ -183,7 +184,7 @@ void testGetConfigHistoryInfoPair() throws Exception {
         configHistoryInfo.setGroup(TEST_GROUP);
         configHistoryInfo.setContent(TEST_CONTENT);
         configHistoryInfo.setTenant(TEST_TENANT);
-        configHistoryInfo.setOpType(TEST_OP_INSERT);
+        configHistoryInfo.setOpType(TEST_OP_TYPE);
         configHistoryInfo.setMd5(TEST_MD5);
         configHistoryInfo.setCreatedTime(new Timestamp(new Date().getTime()));
         configHistoryInfo.setLastModifiedTime(new Timestamp(new Date().getTime()));
@@ -194,7 +195,7 @@ void testGetConfigHistoryInfoPair() throws Exception {
         configHistoryInfoUpdated.setDataId(TEST_DATA_ID);
         configHistoryInfoUpdated.setGroup(TEST_GROUP);
         configHistoryInfoUpdated.setTenant(TEST_TENANT);
-        configHistoryInfoUpdated.setOpType(TEST_OP_INSERT);
+        configHistoryInfoUpdated.setOpType(TEST_OP_TYPE);
         configHistoryInfoUpdated.setMd5(TEST_UPDATED_MD5);
         configHistoryInfoUpdated.setContent(TEST_UPDATED_CONTENT);
         configHistoryInfoUpdated.setCreatedTime(new Timestamp(new Date().getTime()));