diff --git a/mybatis-flex-core/src/main/java/com/mybatisflex/core/util/MapperUtil.java b/mybatis-flex-core/src/main/java/com/mybatisflex/core/util/MapperUtil.java
index 576eeec4..b10b3860 100644
--- a/mybatis-flex-core/src/main/java/com/mybatisflex/core/util/MapperUtil.java
+++ b/mybatis-flex-core/src/main/java/com/mybatisflex/core/util/MapperUtil.java
@@ -25,13 +25,7 @@ import com.mybatisflex.core.field.FieldQuery;
 import com.mybatisflex.core.field.FieldQueryBuilder;
 import com.mybatisflex.core.field.FieldQueryManager;
 import com.mybatisflex.core.paginate.Page;
-import com.mybatisflex.core.query.CPI;
-import com.mybatisflex.core.query.DistinctQueryColumn;
-import com.mybatisflex.core.query.Join;
-import com.mybatisflex.core.query.QueryColumn;
-import com.mybatisflex.core.query.QueryCondition;
-import com.mybatisflex.core.query.QueryTable;
-import com.mybatisflex.core.query.QueryWrapper;
+import com.mybatisflex.core.query.*;
 import com.mybatisflex.core.relation.RelationManager;
 import com.mybatisflex.core.table.TableInfo;
 import com.mybatisflex.core.table.TableInfoFactory;
@@ -75,13 +69,36 @@ public class MapperUtil {
             .select(count().as("total"))
             .from(queryWrapper).as("t");
     }
-
+    public static QueryWrapper rawCountQueryWrapper(QueryWrapper queryWrapper,List<QueryColumn> customCountColumns) {
+        return customCountColumns!=null?QueryWrapper.create()
+            .select(customCountColumns)
+            .from(queryWrapper).as("t"):rawCountQueryWrapper(queryWrapper);
+    }
     /**
      * 优化 COUNT 查询语句。
      */
     public static QueryWrapper optimizeCountQueryWrapper(QueryWrapper queryWrapper) {
+        return optimizeCountQueryWrapper(queryWrapper, Collections.singletonList(count().as("total")));
+    }
+    /**
+     * 优化 COUNT 查询语句。
+     */
+    public static QueryWrapper optimizeCountQueryWrapper(QueryWrapper queryWrapper, List<QueryColumn> customCountColumns) {
         // 对克隆对象进行操作，不影响原来的 QueryWrapper 对象
         QueryWrapper clone = queryWrapper.clone();
+
+        List<UnionWrapper> unions = CPI.getUnions(clone);
+        if(!CollectionUtil.isEmpty(unions)){
+            List<UnionWrapper> newUnions = new ArrayList<>(unions.size());
+            for (UnionWrapper union : unions) {
+                QueryWrapper unionQuery = optimizeCountQueryWrapper(union.getQueryWrapper().clone(),null);
+                UnionWrapper clone1 = union.clone();
+                clone1.setQueryWrapper(unionQuery);
+                newUnions.add(clone1);
+            }
+            CPI.setUnions(clone, newUnions);
+        }
+
         // 将最后面的 order by 移除掉
         CPI.setOrderBys(clone, null);
         // 获取查询列和分组列，用于判断是否进行优化
@@ -91,14 +108,20 @@ public class MapperUtil {
         // 如果有 distinct、group by、having 等语句则不优化
         // 这种一旦优化了就会造成 count 语句查询出来的值不对
         if (hasDistinct(selectColumns) || hasGroupBy(groupByColumns) || havingCondition != null) {
-            return rawCountQueryWrapper(clone);
+            return clone;
         }
         // 判断能不能清除 join 语句
         if (canClearJoins(clone)) {
             CPI.setJoins(clone, null);
         }
         // 将 select 里面的列换成 COUNT(*) AS `total`
-        CPI.setSelectColumns(clone, Collections.singletonList(count().as("total")));
+        if(customCountColumns!=null){
+            if(hasUnion(clone)){
+                return rawCountQueryWrapper(clone,customCountColumns);
+            }else {
+                CPI.setSelectColumns(clone, customCountColumns);
+            }
+        }
         return clone;
     }
 
@@ -118,6 +141,10 @@ public class MapperUtil {
         return CollectionUtil.isNotEmpty(groupByColumns);
     }
 
+    private static boolean hasUnion(QueryWrapper countQueryWrapper) {
+        return CollectionUtil.isNotEmpty(CPI.getUnions(countQueryWrapper));
+    }
+
     private static boolean canClearJoins(QueryWrapper queryWrapper) {
         List<Join> joins = CPI.getJoins(queryWrapper);
         if (CollectionUtil.isEmpty(joins)) {
diff --git a/mybatis-flex-test/mybatis-flex-spring-boot-test/src/test/java/com/mybatisflex/test/common/MapperUtilTest.java b/mybatis-flex-test/mybatis-flex-spring-boot-test/src/test/java/com/mybatisflex/test/common/MapperUtilTest.java
index 0e48c2a3..e420010d 100644
--- a/mybatis-flex-test/mybatis-flex-spring-boot-test/src/test/java/com/mybatisflex/test/common/MapperUtilTest.java
+++ b/mybatis-flex-test/mybatis-flex-spring-boot-test/src/test/java/com/mybatisflex/test/common/MapperUtilTest.java
@@ -45,4 +45,81 @@ class MapperUtilTest {
         System.out.println(MapperUtil.optimizeCountQueryWrapper(queryWrapper).toSQL());
     }
 
+    /**
+     * 测试 (sql1) union (sql2)
+     */
+    @Test
+    void testOptimizeCountQueryWrapperOfUnion1() {
+        //简单union
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
+        QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%'
+        QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test"));
+
+        QueryWrapper query1 = union1.union(union2);
+
+        String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
+        //SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%')) AS `t`
+        System.out.println(sql);
+    }
+
+    /**
+     * 测试 (sql1 ) union (sql2 with group by)
+     */
+    @Test
+    void testOptimizeCountQueryWrapperOfUnion2() {
+        //with group by union
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
+        QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
+        QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).groupBy(USER.USER_ID, USER.USER_NAME);
+
+        QueryWrapper query1 = union1.union(union2);
+
+        //SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' GROUP BY `user_id`, `user_name`)) AS `t`
+        String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
+        System.out.println(sql);
+    }
+
+    /**
+     * 测试 (sql1) union (sql2 union sql3)
+     */
+    @Test
+    void testOptimizeCountQueryWrapperOfUnion3() {
+        //with sub query union
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
+        QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
+        QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).orderBy(USER.USER_NAME.desc());
+
+        QueryWrapper union3 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.PASSWORD.isNull()).orderBy(USER.USER_NAME.desc());
+
+
+        QueryWrapper query1 = union1.union(union2.union(union3));
+
+        //SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%') UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `password` IS NULL ))) AS `t`
+        String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
+
+        System.out.println(sql);
+    }
+
+    @Test
+    void testOptimizeCountQueryWrapperOfUnion4() {
+        //with sub query union
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
+        QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
+        //SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
+        QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).orderBy(USER.USER_NAME.desc());
+
+        QueryWrapper union3 = QueryWrapper.create().from(union2).as("a");
+
+
+        QueryWrapper query1 = union1.union(union3);
+
+        //SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%') UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `password` IS NULL ))) AS `t`
+        String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
+
+        System.out.println(sql);
+    }
+
 }