diff --git a/OrmTest/ExpressionTest/Method.cs b/OrmTest/ExpressionTest/Method.cs
index 5aa74f4eb..62b5f724a 100644
--- a/OrmTest/ExpressionTest/Method.cs
+++ b/OrmTest/ExpressionTest/Method.cs
@@ -27,6 +27,7 @@ namespace OrmTest.ExpressionTest
                 StringIsNullOrEmpty3();
                 StringIsNullOrEmpty4();
                 ToUpper();
+                ToLower();
                 #endregion
             }
             base.End("Method Test");
@@ -34,15 +35,26 @@ namespace OrmTest.ExpressionTest
 
         private void ToUpper()
         {
-            Expression<Func<Student, bool>> exp = it =>"a"== NBORM.ToLower(it.Id) ;
+            Expression<Func<Student, bool>> exp = it =>"a"== NBORM.ToUpper(it.Id) ;
             SqlServerExpressionContext expContext = new SqlServerExpressionContext(exp, ResolveExpressType.WhereSingle);
             expContext.Resolve();
             var value = expContext.Result.GetString();
             var pars = expContext.Parameters;
-            base.Check(value, pars, "(( Id  > @Id0 )  OR  ( Id='' OR Id IS NULL ))", new List<SugarParameter>() {
-                new SugarParameter("@Id0",2)
+            base.Check(value, pars, "( @Const0  = (UPPER(Id)) )", new List<SugarParameter>() {
+                new SugarParameter("@Const0","a")
             }, "ToUpper");
         }
+        private void ToLower()
+        {
+            Expression<Func<Student, bool>> exp = it => "a" == NBORM.ToLower(it.Id);
+            SqlServerExpressionContext expContext = new SqlServerExpressionContext(exp, ResolveExpressType.WhereSingle);
+            expContext.Resolve();
+            var value = expContext.Result.GetString();
+            var pars = expContext.Parameters;
+            base.Check(value, pars, "( @Const0  = (LOWER(Id)) )", new List<SugarParameter>() {
+                new SugarParameter("@Const0","a")
+            }, "ToLower");
+        }
 
         #region StringIsNullOrEmpty
         private void StringIsNullOrEmpty()
@@ -63,8 +75,8 @@ namespace OrmTest.ExpressionTest
             expContext.Resolve();
             var value = expContext.Result.GetString();
             var pars = expContext.Parameters;
-            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodCost1='' OR @MethodCost1 IS NULL ))", new List<SugarParameter>() {
-                new SugarParameter("@MethodCost1",true),
+            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodConst1='' OR @MethodConst1 IS NULL ))", new List<SugarParameter>() {
+                new SugarParameter("@MethodConst1",true),
                 new SugarParameter("@Id0",2)
             }, "StringIsNullOrEmpty2");
         }
@@ -76,8 +88,8 @@ namespace OrmTest.ExpressionTest
             expContext.Resolve();
             var value = expContext.Result.GetString();
             var pars = expContext.Parameters;
-            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodCost1='' OR @MethodCost1 IS NULL ))", new List<SugarParameter>() {
-                new SugarParameter("@MethodCost1",1),
+            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodConst1='' OR @MethodConst1 IS NULL ))", new List<SugarParameter>() {
+                new SugarParameter("@MethodConst1",1),
                 new SugarParameter("@Id0",2)
             }, "StringIsNullOrEmpty3");
         }
@@ -89,8 +101,8 @@ namespace OrmTest.ExpressionTest
             expContext.Resolve();
             var value = expContext.Result.GetString();
             var pars = expContext.Parameters;
-            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodCost1='' OR @MethodCost1 IS NULL ))", new List<SugarParameter>() {
-                new SugarParameter("@MethodCost1","xx"),
+            base.Check(value, pars, "(( @Id0  = Id )  OR  ( @MethodConst1='' OR @MethodConst1 IS NULL ))", new List<SugarParameter>() {
+                new SugarParameter("@MethodConst1","xx"),
                 new SugarParameter("@Id0",2)
             }, "StringIsNullOrEmpty4");
         } 
diff --git a/SqlSugar/ExpressionsToSql/Common/ExpressionConst.cs b/SqlSugar/ExpressionsToSql/Common/ExpressionConst.cs
index b2863b868..94f2210b5 100644
--- a/SqlSugar/ExpressionsToSql/Common/ExpressionConst.cs
+++ b/SqlSugar/ExpressionsToSql/Common/ExpressionConst.cs
@@ -14,7 +14,8 @@ namespace SqlSugar
         public const string Format3 = "(";
         public const string Format4 = ")";
         public const string NBORMFULLNAME = "SqlSugar.NBORM";
-        public const string METHODCOST = "MethodCost";
+        public const string METHODCONST = "MethodConst";
+        public const string CONST = "Const";
         public readonly static Type MemberExpressionType = typeof(MemberExpression);
         public readonly static Type ConstantExpressionType = typeof(ConstantExpression);
         public readonly static Type StringType = typeof(string);
diff --git a/SqlSugar/ExpressionsToSql/Method/DefaultDbMethod.cs b/SqlSugar/ExpressionsToSql/Method/DefaultDbMethod.cs
index 6f5a94f92..f5b42f152 100644
--- a/SqlSugar/ExpressionsToSql/Method/DefaultDbMethod.cs
+++ b/SqlSugar/ExpressionsToSql/Method/DefaultDbMethod.cs
@@ -13,13 +13,13 @@ namespace SqlSugar
             return string.Format("( {0}='' OR {0} IS NULL )", parameter.Value);
         }
 
-        public object ToUpper(MethodCallExpressionModel model)
+        public virtual object ToUpper(MethodCallExpressionModel model)
         {
             var parameter = model.Args[0];
             return string.Format(" (UPPER({0})) ", parameter.Value);
         }
 
-        public object ToLower(MethodCallExpressionModel model)
+        public virtual object ToLower(MethodCallExpressionModel model)
         {
             var parameter = model.Args[0];
             return string.Format(" (LOWER({0})) ", parameter.Value);
diff --git a/SqlSugar/ExpressionsToSql/ResolveItems/BaseResolve.cs b/SqlSugar/ExpressionsToSql/ResolveItems/BaseResolve.cs
index e0cc35250..f361bab6e 100644
--- a/SqlSugar/ExpressionsToSql/ResolveItems/BaseResolve.cs
+++ b/SqlSugar/ExpressionsToSql/ResolveItems/BaseResolve.cs
@@ -124,9 +124,24 @@ namespace SqlSugar
                         this.Context.Result.Append(parameterName);
                     }
                 }
-                else
+                else 
                 {
-
+                    var parameterName =this.Context.SqlParameterKeyWord+ExpressionConst.CONST +Context.ParameterIndex;
+                    Context.ParameterIndex++;
+                    this.Context.Parameters.Add(new SugarParameter(parameterName,value));
+                    parameterName = string.Format(" {0} ", parameterName);
+                    if (isLeft == true)
+                    {
+                        parameterName += ExpressionConst.Format1 + parameter.BaseParameter.Index;
+                    }
+                    if (this.Context.Result.Contains(ExpressionConst.Format0))
+                    {
+                        this.Context.Result.Replace(ExpressionConst.Format0, parameterName);
+                    }
+                    else
+                    {
+                        this.Context.Result.Append(parameterName);
+                    }
                 }
             }
         }
diff --git a/SqlSugar/ExpressionsToSql/ResolveItems/ConstantExpressionResolve.cs b/SqlSugar/ExpressionsToSql/ResolveItems/ConstantExpressionResolve.cs
index c6065c81a..cb15a54ff 100644
--- a/SqlSugar/ExpressionsToSql/ResolveItems/ConstantExpressionResolve.cs
+++ b/SqlSugar/ExpressionsToSql/ResolveItems/ConstantExpressionResolve.cs
@@ -31,6 +31,7 @@ namespace SqlSugar
                     {
                         AppendParameter(parameter, isLeft, value);
                     }
+
                     break;
                 case ResolveExpressType.FieldSingle:
                 case ResolveExpressType.FieldMultiple:
diff --git a/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs b/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs
index 6acf8ccf6..4a94030ec 100644
--- a/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs
+++ b/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs
@@ -42,7 +42,7 @@ namespace SqlSugar
                         }
                         if (methodCallExpressionArgs.IsMember == false)
                         {
-                            var parameterName = this.Context.SqlParameterKeyWord + ExpressionConst.METHODCOST + this.Context.ParameterIndex;
+                            var parameterName = this.Context.SqlParameterKeyWord + ExpressionConst.METHODCONST + this.Context.ParameterIndex;
                             this.Context.ParameterIndex++;
                             methodCallExpressionArgs.Value = parameterName;
                             this.Context.Parameters.Add(new SugarParameter(parameterName, value));
@@ -69,6 +69,8 @@ namespace SqlSugar
                     return this.Context.DbMehtods.IsNullOrEmpty(model);
                 case "ToLower":
                     return this.Context.DbMehtods.ToLower(model);
+                case "ToUpper":
+                    return this.Context.DbMehtods.ToUpper(model);
                 default:
                     break;
             }