diff --git a/src/common/backend/parser/parse_coerce.cpp b/src/common/backend/parser/parse_coerce.cpp
index 02fb56e2d..ed16ec6c5 100644
--- a/src/common/backend/parser/parse_coerce.cpp
+++ b/src/common/backend/parser/parse_coerce.cpp
@@ -212,20 +212,23 @@ Node* coerce_to_target_type(ParseState* pstate, Node* expr, Oid exprtype, Oid ta
             (cformat != COERCE_IMPLICIT_CAST),
             (result != expr && !IsA(result, Const)));
     }
-#ifdef PGXC
-    /* Do not need to do that on local Coordinator */
-    if (IsConnFromCoord())
-#endif
-        if (expr != origexpr) {
-            /* Reinstall top CollateExpr */
-            CollateExpr* coll = (CollateExpr*)origexpr;
-            CollateExpr* newcoll = makeNode(CollateExpr);
 
-            newcoll->arg = (Expr*)result;
-            newcoll->collOid = coll->collOid;
-            newcoll->location = coll->location;
-            result = (Node*)newcoll;
-        }
+    if (expr != origexpr && (
+#ifdef PGXC
+        /* Do not need to do that on local Coordinator */
+        IsConnFromCoord() ||
+#endif
+        type_is_collatable(targettype))) {
+
+        /* Reinstall top CollateExpr */
+        CollateExpr* coll = (CollateExpr*)origexpr;
+        CollateExpr* newcoll = makeNode(CollateExpr);
+
+        newcoll->arg = (Expr*)result;
+        newcoll->collOid = coll->collOid;
+        newcoll->location = coll->location;
+        result = (Node*)newcoll;
+    }
 
     return result;
 }
diff --git a/src/test/regress/expected/charset_utf8mb4_b_db.out b/src/test/regress/expected/charset_utf8mb4_b_db.out
index 736fe0c22..5fead0c32 100644
--- a/src/test/regress/expected/charset_utf8mb4_b_db.out
+++ b/src/test/regress/expected/charset_utf8mb4_b_db.out
@@ -371,6 +371,63 @@ SELECT '高斯' COLLATE "binary"; -- ERROR
 ERROR:  COLLATION "binary" is not valid for CHARACTER SET "UTF8"
 LINE 1: SELECT '高斯' COLLATE "binary";
                       ^
+-- test CollateExpr
+CREATE TABLE t_collate_expr(
+    ftext text collate utf8mb4_bin,
+    fbytea bytea,
+    fvbit varbit(8),
+    fint int
+);
+-- -- test INSERT
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate "binary"); -- ERROR
+ERROR:  COLLATION "binary" is not valid for CHARACTER SET "UTF8"
+LINE 1: ...SERT INTO t_collate_expr(ftext) VALUES('01100001' collate "b...
+                                                             ^
+CONTEXT:  referenced column: ftext
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate gbk_bin); -- ERROR
+ERROR:  COLLATION "gbk_bin" is not valid for CHARACTER SET "UTF8"
+LINE 1: ...SERT INTO t_collate_expr(ftext) VALUES('01100001' collate gb...
+                                                             ^
+CONTEXT:  referenced column: ftext
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- only reserve top collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+-- -- test limit
+select 1 from t_collate_expr limit(to_hex('11') collate "binary");
+ ?column? 
+----------
+(0 rows)
+
+select 1 from t_collate_expr limit(to_hex('11') collate gbk_bin);
+ ?column? 
+----------
+(0 rows)
+
+select 1 from t_collate_expr limit(to_hex('11') collate utf8mb4_unicode_ci);
+ ?column? 
+----------
+(0 rows)
+
+select 1 from t_collate_expr limit(to_hex('11') collate gbk_bin collate utf8mb4_unicode_ci);  -- do not check collate
+ ?column? 
+----------
+(0 rows)
+
+DROP TABLE t_collate_expr;
 -- 中文 const charset
 SELECT CAST('高斯' AS bytea);
      bytea      
@@ -2287,18 +2344,16 @@ EXECUTE test_merge_collation(_utf8mb4'高斯DB'); -- $1 use collation_connection
  高斯DB高斯DB | utf8mb4_general_ci
 (1 row)
 
-EXECUTE test_merge_collation(_utf8mb4'高斯DB' collate gbk_chinese_ci); -- explicit noneffective, utf8_gen
-    result    |  pg_collation_for  
---------------+--------------------
- 高斯DB高斯DB | utf8mb4_general_ci
-(1 row)
-
 EXECUTE test_merge_collation(_gbk'高斯DB'); -- _gbk noneffective, utf8_gen
     result    |  pg_collation_for  
 --------------+--------------------
  高斯DB高斯DB | utf8mb4_general_ci
 (1 row)
 
+EXECUTE test_merge_collation(_utf8mb4'高斯DB' collate gbk_chinese_ci); -- implicit type cast, keep explicit collation and check it, ERROR
+ERROR:  COLLATION "gbk_chinese_ci" is not valid for CHARACTER SET "UTF8"
+LINE 1: EXECUTE test_merge_collation(_utf8mb4'高斯DB' collate gbk_ch...
+                                                      ^
 DEALLOCATE test_merge_collation;
 -- -- -- -- PBE with explicit collation,
 PREPARE test_merge_collation(text) AS
diff --git a/src/test/regress/sql/charset_utf8mb4_b_db.sql b/src/test/regress/sql/charset_utf8mb4_b_db.sql
index bf0dd844a..a6ab68d58 100644
--- a/src/test/regress/sql/charset_utf8mb4_b_db.sql
+++ b/src/test/regress/sql/charset_utf8mb4_b_db.sql
@@ -91,6 +91,42 @@ SELECT '高斯' COLLATE "gbk_chinese_ci"; -- ERROR
 SELECT '高斯' COLLATE "gb18030_chinese_ci"; -- ERROR
 SELECT '高斯' COLLATE "binary"; -- ERROR
 
+-- test CollateExpr
+CREATE TABLE t_collate_expr(
+    ftext text collate utf8mb4_bin,
+    fbytea bytea,
+    fvbit varbit(8),
+    fint int
+);
+-- -- test INSERT
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate "binary"); -- ERROR
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate gbk_bin); -- ERROR
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(ftext) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- only reserve top collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate "binary"); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate utf8mb4_unicode_ci);
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fbytea) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fvbit) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate gbk_bin collate utf8mb4_unicode_ci); -- do not check collate
+INSERT INTO t_collate_expr(fint) VALUES('01100001' collate utf8mb4_general_ci collate gbk_bin); -- do not check collate
+
+-- -- test limit
+select 1 from t_collate_expr limit(to_hex('11') collate "binary");
+select 1 from t_collate_expr limit(to_hex('11') collate gbk_bin);
+select 1 from t_collate_expr limit(to_hex('11') collate utf8mb4_unicode_ci);
+select 1 from t_collate_expr limit(to_hex('11') collate gbk_bin collate utf8mb4_unicode_ci);  -- do not check collate
+
+DROP TABLE t_collate_expr;
+
 -- 中文 const charset
 SELECT CAST('高斯' AS bytea);
 SELECT CAST(_binary'高斯' AS bytea);
@@ -544,8 +580,8 @@ DEALLOCATE test_merge_collation;
 PREPARE test_merge_collation(text) AS
 SELECT CONCAT($1, fgbk_bin) result, collation for(result) FROM t_diff_charset_columns;
 EXECUTE test_merge_collation(_utf8mb4'高斯DB'); -- $1 use collation_connection, utf8_gen
-EXECUTE test_merge_collation(_utf8mb4'高斯DB' collate gbk_chinese_ci); -- explicit noneffective, utf8_gen
 EXECUTE test_merge_collation(_gbk'高斯DB'); -- _gbk noneffective, utf8_gen
+EXECUTE test_merge_collation(_utf8mb4'高斯DB' collate gbk_chinese_ci); -- implicit type cast, keep explicit collation and check it, ERROR
 DEALLOCATE test_merge_collation;
 -- -- -- -- PBE with explicit collation,
 PREPARE test_merge_collation(text) AS