diff --git a/src/share/object/ob_obj_cast.cpp b/src/share/object/ob_obj_cast.cpp
index 28b46f6971..02b74c0d3f 100644
--- a/src/share/object/ob_obj_cast.cpp
+++ b/src/share/object/ob_obj_cast.cpp
@@ -34,6 +34,8 @@
 #include "lib/geo/ob_geometry_cast.h"
 #include "sql/engine/expr/ob_datum_cast.h"
 #include "sql/engine/expr/ob_expr_util.h"
+#include "src/storage/lob/ob_lob_manager.h"
+#include "sql/engine/expr/ob_expr_json_func_helper.h"
 #ifdef OB_BUILD_ORACLE_XML
 #include "lib/xml/ob_xml_util.h"
 #include "lib/xml/ob_xml_parser.h"
@@ -14350,7 +14352,7 @@ int ObObjCaster::to_type(const ObExpectType &expect_type,
   return ret;
 }
 
-const char OB_JSON_NULL[2] = {'\0', '\0'}; // binary json null
+const ObJsonZeroVal OB_JSON_ZERO = ObJsonZeroVal(); // binary json null
 
 int ObObjCaster::get_zero_value(const ObObjType expect_type, ObCollationType expect_cs_type, ObObj &zero_obj)
 {
@@ -14358,10 +14360,15 @@ int ObObjCaster::get_zero_value(const ObObjType expect_type, ObCollationType exp
   ObObjCastParams params; //构造一个空的cast_param对象，适配SET_RES_XXX宏定义
   ObCastMode cast_mode = CM_WARN_ON_FAIL;
   params.warning_ = 1; //将warning code设置为1，避免SET_RES_XXX宏将其当做真实的warning处理
-  if (ob_is_string_tc(expect_type) || ob_is_text_tc(expect_type)) {
+  if (ob_is_string_tc(expect_type)) {
     zero_obj.set_string(expect_type, "");
   } else if (ob_is_text_tc(expect_type)) {
-    zero_obj.set_lob_value(expect_type, static_cast<const char *>(NULL), 0);
+    if (ob_is_large_text(expect_type)) {
+      zero_obj.set_lob_value(expect_type, reinterpret_cast<const char *>(&ObLobManager::ZERO_LOB), sizeof(ObLobCommon));
+      zero_obj.set_has_lob_header();
+    } else { // tinytext
+      zero_obj.set_string(expect_type, "");
+    }
   } else if (ob_is_int_tc(expect_type)) {
     int64_t value = 0;
     SET_RES_INT(zero_obj);
@@ -14412,7 +14419,8 @@ int ObObjCaster::get_zero_value(const ObObjType expect_type, ObCollationType exp
     ret = OB_NOT_SUPPORTED;
     LOG_WARN("urowid with default value not supported");
   } else if (expect_type == ObJsonType) {
-    zero_obj.set_json_value(expect_type, OB_JSON_NULL, 2);
+    zero_obj.set_json_value(expect_type, reinterpret_cast<const char *>(&OB_JSON_ZERO), ObJsonZeroVal::OB_JSON_ZERO_VAL_LENGTH);
+    zero_obj.set_has_lob_header();
   } else if (expect_type == ObDecimalIntType) {
     zero_obj.set_decimal_int(0, 0, nullptr);
   } else if (ob_is_user_defined_sql_type(expect_type)) {
diff --git a/src/sql/engine/dml/ob_dml_service.cpp b/src/sql/engine/dml/ob_dml_service.cpp
index 631c09a10f..5b1c84d82b 100644
--- a/src/sql/engine/dml/ob_dml_service.cpp
+++ b/src/sql/engine/dml/ob_dml_service.cpp
@@ -119,15 +119,11 @@ int ObDMLService::check_row_null(const ObExprPtrIArray &row,
                                                                   res_alloc,
                                                                   zero_obj))) {
           LOG_WARN("padding fixed string value failed", K(ret));
-        } else if (OB_FAIL(ObTextStringResult::ob_convert_obj_temporay_lob(zero_obj, eval_ctx.exec_ctx_.get_allocator()))) {
-          LOG_WARN("convert lob types zero obj failed", K(ret), K(zero_obj));
-        } else if (OB_FAIL(!is_decimal_int && row_datum.from_obj(zero_obj))) {
+        } else if (!is_decimal_int && OB_FAIL(row_datum.from_obj(zero_obj))) {
           LOG_WARN("assign zero obj to datum failed", K(ret), K(zero_obj));
-        } else if (is_lob_storage(zero_obj.get_type()) &&
-                   OB_FAIL(ob_adjust_lob_datum(zero_obj, row.at(col_idx)->obj_meta_,
-                                               eval_ctx.exec_ctx_.get_allocator(),
-                                               row_datum))) {
-          LOG_WARN("adjust lob datum failed", K(ret), K(i), K(col_idx),
+        } else if (zero_obj.is_lob_storage() && zero_obj.has_lob_header() != row.at(col_idx)->obj_meta_.has_lob_header()) {
+          ret = OB_ERR_UNEXPECTED;
+          LOG_WARN("has lob header mark is wrong", K(ret), K(i), K(col_idx),
             K(zero_obj.get_meta()), K(row.at(col_idx)->obj_meta_));
         } else {
           //output warning msg
diff --git a/src/sql/engine/expr/ob_expr_json_func_helper.h b/src/sql/engine/expr/ob_expr_json_func_helper.h
index a72a04e7a3..ceb6e7d015 100644
--- a/src/sql/engine/expr/ob_expr_json_func_helper.h
+++ b/src/sql/engine/expr/ob_expr_json_func_helper.h
@@ -251,6 +251,17 @@ private:
   DISALLOW_COPY_AND_ASSIGN(ObJsonExprHelper);
 };
 
+struct ObJsonZeroVal
+{
+  static const int32_t OB_JSON_ZERO_VAL_LENGTH = sizeof(ObLobCommon) + 2;
+  ObJsonZeroVal() : header_(), json_bin_() {
+    json_bin_[0] = '\0';
+    json_bin_[1] = '\0';
+  }
+  ObLobCommon header_;
+  char json_bin_[4];
+};
+
 } // sql
 } // oceanbase
 #endif // OCEANBASE_SQL_OB_EXPR_JSON_FUNC_HELPER_H_
\ No newline at end of file
diff --git a/src/storage/lob/ob_lob_manager.cpp b/src/storage/lob/ob_lob_manager.cpp
index 1599f2e1ec..036bdd92dd 100644
--- a/src/storage/lob/ob_lob_manager.cpp
+++ b/src/storage/lob/ob_lob_manager.cpp
@@ -25,6 +25,8 @@ namespace oceanbase
 namespace storage
 {
 
+const ObLobCommon ObLobManager::ZERO_LOB = ObLobCommon();
+
 int ObLobManager::mtl_new(ObLobManager *&m) {
   int ret = OB_SUCCESS;
   const uint64_t tenant_id = MTL_ID();
diff --git a/src/storage/lob/ob_lob_manager.h b/src/storage/lob/ob_lob_manager.h
index f7eeece0f4..0e82c3b49c 100644
--- a/src/storage/lob/ob_lob_manager.h
+++ b/src/storage/lob/ob_lob_manager.h
@@ -141,6 +141,7 @@ public:
   static const uint64_t LOB_READ_BUFFER_LEN = 1024L*1024L; // 1M
   static const int64_t LOB_IN_ROW_MAX_LENGTH = 4096; // 4K
   static const uint64_t REMOTE_LOB_QUERY_RETRY_MAX = 10L; // 1M
+  static const ObLobCommon ZERO_LOB; // static empty lob for zero val
 private:
   explicit ObLobManager(const uint64_t tenant_id)
     : tenant_id_(tenant_id),