diff --git a/Src/Asp.Net/SqlSugar/Abstract/CodeFirstProvider/CodeFirstProvider.cs b/Src/Asp.Net/SqlSugar/Abstract/CodeFirstProvider/CodeFirstProvider.cs
index dbdf28698..4235e905f 100644
--- a/Src/Asp.Net/SqlSugar/Abstract/CodeFirstProvider/CodeFirstProvider.cs
+++ b/Src/Asp.Net/SqlSugar/Abstract/CodeFirstProvider/CodeFirstProvider.cs
@@ -231,6 +231,10 @@ namespace SqlSugar
                         {
                             item.DataType = mappingType;
                         }
+                        if (item.DataType == "varcharmax") 
+                        {
+                            item.DataType = "nvarchar(max)";
+                        }
                     }
                 }
             }
diff --git a/Src/Asp.Net/SqlSugar/Infrastructure/StaticConfig.cs b/Src/Asp.Net/SqlSugar/Infrastructure/StaticConfig.cs
index 7959d92b6..5d7346f63 100644
--- a/Src/Asp.Net/SqlSugar/Infrastructure/StaticConfig.cs
+++ b/Src/Asp.Net/SqlSugar/Infrastructure/StaticConfig.cs
@@ -8,5 +8,6 @@ namespace SqlSugar
     {
         public static Func<string,string> Encode { get; set; }
         public static Func<string,string> Decode{ get; set; }
+        public const string CodeFirt_BigString = "varcharmax,longtext,text,clob";
     }
 }
diff --git a/Src/Asp.Net/SqlSugar/Realization/SqlServer/DbBind/SqlServerDbBind.cs b/Src/Asp.Net/SqlSugar/Realization/SqlServer/DbBind/SqlServerDbBind.cs
index 94e94f06e..fb0e65887 100644
--- a/Src/Asp.Net/SqlSugar/Realization/SqlServer/DbBind/SqlServerDbBind.cs
+++ b/Src/Asp.Net/SqlSugar/Realization/SqlServer/DbBind/SqlServerDbBind.cs
@@ -38,6 +38,7 @@ namespace SqlSugar
                   new KeyValuePair<string, CSharpDataType>("varchar",CSharpDataType.@string),
                   new KeyValuePair<string, CSharpDataType>("nvarchar",CSharpDataType.@string),
                   new KeyValuePair<string, CSharpDataType>("sql_variant",CSharpDataType.@string),
+                  new KeyValuePair<string, CSharpDataType>("varcharmax",CSharpDataType.@string),
                   new KeyValuePair<string, CSharpDataType>("text",CSharpDataType.@string),
                   new KeyValuePair<string, CSharpDataType>("char",CSharpDataType.@string),
                   new KeyValuePair<string, CSharpDataType>("ntext",CSharpDataType.@string),