diff --git a/FreeSql.Tests.VB/UnitTest1.vb b/FreeSql.Tests.VB/UnitTest1.vb
index c8966d58..d9e12fa3 100644
--- a/FreeSql.Tests.VB/UnitTest1.vb
+++ b/FreeSql.Tests.VB/UnitTest1.vb
@@ -4,6 +4,17 @@ Imports Xunit
 
 Namespace FreeSql.Tests.VB
     Public Class UnitTest1
+
+        <Fact>
+        Sub IsNothing()
+            Dim sql = g.sqlserver.Select(Of Testvb).Where(Function(a) a.Id = 100 AndAlso a.Title Is Nothing).ToSql()
+            Assert.Equal("SELECT a.[Id], a.[Title], a.[IsDeleted], a.[IdNullable] 
+FROM [Testvb] a 
+WHERE (a.[Id] = 100 AND a.[Title]  IS  NULL)", sql)
+
+            Dim lst = g.sqlserver.Select(Of Testvb).Where(Function(a) a.Id = 100 AndAlso a.Title Is Nothing).ToList()
+        End Sub
+
         <Fact>
         Sub TestSub()
 
diff --git a/FreeSql/Internal/CommonExpression.cs b/FreeSql/Internal/CommonExpression.cs
index 01004c01..fe9e51ab 100644
--- a/FreeSql/Internal/CommonExpression.cs
+++ b/FreeSql/Internal/CommonExpression.cs
@@ -499,9 +499,9 @@ namespace FreeSql.Internal
                 case "=":
                 case "<>":
                     var exptb = _common.GetTableByEntity(leftExp.Type);
-                    if (exptb != null) leftExp = Expression.MakeMemberAccess(leftExp, exptb.Properties[(exptb.Primarys.FirstOrDefault() ?? exptb.Columns.FirstOrDefault().Value).CsName]);
+                    if (exptb?.Properties.Any() == true) leftExp = Expression.MakeMemberAccess(leftExp, exptb.Properties[(exptb.Primarys.FirstOrDefault() ?? exptb.Columns.FirstOrDefault().Value)?.CsName]);
                     exptb = _common.GetTableByEntity(leftExp.Type);
-                    if (exptb?.Primarys.Any() == true) rightExp = Expression.MakeMemberAccess(rightExp, exptb.Properties[(exptb.Primarys.FirstOrDefault() ?? exptb.Columns.FirstOrDefault().Value).CsName]);
+                    if (exptb?.Properties.Any() == true) rightExp = Expression.MakeMemberAccess(rightExp, exptb.Properties[(exptb.Primarys.FirstOrDefault() ?? exptb.Columns.FirstOrDefault().Value).CsName]);
                     break;
             }