diff --git a/Src/Asp.NetCore2/SqlSeverTest/UnitTest/UCodeFirst.cs b/Src/Asp.NetCore2/SqlSeverTest/UnitTest/UCodeFirst.cs
index f80ffa02b..d70b360a3 100644
--- a/Src/Asp.NetCore2/SqlSeverTest/UnitTest/UCodeFirst.cs
+++ b/Src/Asp.NetCore2/SqlSeverTest/UnitTest/UCodeFirst.cs
@@ -15,8 +15,31 @@ namespace OrmTest
                 Db.DbMaintenance.DropTable("UnitCodeTest1");
             Db.CodeFirst.InitTables<UnitCodeTest1>();
             Db.CodeFirst.InitTables<UnitCodeFirstpks2>();
+            if (Db.DbMaintenance.IsAnyTable("UnitCodeFirst131", false))
+                Db.DbMaintenance.DropTable("UnitCodeFirst131");
+            Db.CodeFirst.InitTables<UnitCodeFirst131>();
+            Db.Insertable(new UnitCodeFirst131() { Id = 1 }).ExecuteCommand();
+            Db.CodeFirst.InitTables<UNITCODEFIRST131>();
+            Db.CodeFirst.InitTables<UNITCOdEFIRST131>();
+        }
+        public class UnitCodeFirst131 
+        {
+            public int Id { get; set; } 
+        }
+        public class UNITCODEFIRST131
+        {
+            public int Id { get; set; }
+            [SqlSugar.SugarColumn(DefaultValue ="a")]
+            public string Name { get; set; }
+        }
+        public class UNITCOdEFIRST131
+        {
+            public int Id { get; set; }
+            [SqlSugar.SugarColumn(DefaultValue = "a")]
+            public string Name { get; set; }
+            [SqlSugar.SugarColumn(DefaultValue = "getdate()")]
+            public DateTime dt { get; set; }
         }
-
         public class UnitCodeFirstpks2
         {
             [SqlSugar.SugarColumn(IsPrimaryKey =true)]
diff --git a/Src/Asp.NetCore2/SqlSugar/Abstract/DbMaintenanceProvider/Methods.cs b/Src/Asp.NetCore2/SqlSugar/Abstract/DbMaintenanceProvider/Methods.cs
index ddf896151..73b02d198 100644
--- a/Src/Asp.NetCore2/SqlSugar/Abstract/DbMaintenanceProvider/Methods.cs
+++ b/Src/Asp.NetCore2/SqlSugar/Abstract/DbMaintenanceProvider/Methods.cs
@@ -196,8 +196,27 @@ namespace SqlSugar
         public virtual bool AddColumn(string tableName, DbColumnInfo columnInfo)
         {
             tableName = this.SqlBuilder.GetTranslationTableName(tableName);
+            var isAddNotNUll = columnInfo.IsNullable == false && columnInfo.DefaultValue.HasValue();
+            if (isAddNotNUll)
+            {
+                columnInfo = this.Context.Utilities.TranslateCopy(columnInfo);
+                columnInfo.IsNullable = true;
+            }
             string sql = GetAddColumnSql(tableName, columnInfo);
             this.Context.Ado.ExecuteCommand(sql);
+            if (isAddNotNUll) 
+            {
+                var dtColums = this.Context.Queryable<object>().AS(columnInfo.TableName).Where("1=2").ToDataTable().Columns.Cast<System.Data.DataColumn>();
+                var dtColumInfo = dtColums.First(it => it.ColumnName.EqualCase(columnInfo.DbColumnName));
+                var type = UtilMethods.GetUnderType(dtColumInfo.DataType);
+                var value= type==UtilConstants.StringType?(object)"": Activator.CreateInstance(type);
+                var dt = new Dictionary<string, object>();
+                dt.Add(columnInfo.DbColumnName, value);
+                this.Context.Updateable(dt)
+                             .AS(tableName)
+                             .Where($"{columnInfo.DbColumnName} is null ").ExecuteCommand();
+                UpdateColumn(tableName, columnInfo);
+            }
             return true;
         }
         public virtual bool UpdateColumn(string tableName, DbColumnInfo column)