diff --git a/liteyuki/utils/data.py b/liteyuki/utils/data.py
index c22361d0..0c2d5556 100644
--- a/liteyuki/utils/data.py
+++ b/liteyuki/utils/data.py
@@ -238,7 +238,7 @@ class Database:
             # 检测缺失字段，由于SQLite是动态类型，所以不需要检测类型
             for n_field, n_type in new_structure.items():
                 if n_field not in existing_structure.keys() and n_field.lower() not in ["id", "table_name"]:
-                    default_value = self.DEFAULT_MAPPING.get(n_type, "''")
+                    default_value = self.DEFAULT_MAPPING.get(n_type, 'NULL')
                     self.cursor.execute(
                         f"ALTER TABLE '{model.TABLE_NAME}' ADD COLUMN {n_field} {n_type} DEFAULT {self.DEFAULT_MAPPING.get(n_type, default_value)}"
                     )
@@ -320,7 +320,7 @@ class Database:
             "TEXT"   : "''",
             "INTEGER": 0,
             "REAL"   : 0.0,
-            "BLOB"   : b"",
+            "BLOB"   : None,
             "NULL"   : None
     }