diff --git a/Src/Asp.NetCore2/MongoDbTest/UnitTest/QuerySelect.cs b/Src/Asp.NetCore2/MongoDbTest/UnitTest/QuerySelect.cs
index bd13a045f..82d4b54d4 100644
--- a/Src/Asp.NetCore2/MongoDbTest/UnitTest/QuerySelect.cs
+++ b/Src/Asp.NetCore2/MongoDbTest/UnitTest/QuerySelect.cs
@@ -170,7 +170,25 @@ namespace MongoDbTest
              { 
                  name = it.Name.Length,
              }).ToList();
-            if(list18.Max(it=>it.name)!=2) Cases.ThrowUnitError(); 
+            if(list18.Max(it=>it.name)!=2) Cases.ThrowUnitError();
+
+            var list19= db.Queryable<Student>()
+           .Select(it => new
+           {
+               name =string.IsNullOrEmpty(it.Name),
+           }).ToList();
+            if (list19.Max(it => it.name) != true) Cases.ThrowUnitError();
+
+            //var list20 = db.Queryable<Student>()
+            //  .Select(it => new
+            //  {
+            //      name = string.IsNullOrEmpty(it.Name).ToString(),
+            //  }).ToList();
+            //if (list20.Max(it => it.name) != "true") Cases.ThrowUnitError();
+             
+            var list22= db.Queryable<Student>()
+            .Select(it=>it.Name).ToList();
+            if (list22.First() != "a") Cases.ThrowUnitError();
         }
         [SqlSugar.SugarTable("UnitStudent1231sds3z1")]
         public class Student : MongoDbBase
diff --git a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/ExpToSql/MongoDbExpTools.cs b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/ExpToSql/MongoDbExpTools.cs
index 3f2be2ee9..977c503f3 100644
--- a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/ExpToSql/MongoDbExpTools.cs
+++ b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/ExpToSql/MongoDbExpTools.cs
@@ -1,4 +1,5 @@
-using System;
+using MongoDB.Bson;
+using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.Linq.Expressions;
@@ -7,7 +8,18 @@ using System.Text;
 namespace SqlSugar.MongoDb 
 {
     public class MongoDbExpTools
-    { 
+    {
+
+        public static bool IsFieldNameJson(string trimmed)
+        {
+            return trimmed.StartsWith("{ \"fieldName\" : ");
+        }
+        public static bool IsFieldNameJson(BsonDocument doc)
+        {
+            if (doc.Contains("fieldName"))
+                return true;
+            return false;
+        }
         public static string CustomToString(object value)
         {
             if (value == null||value==DBNull.Value)
diff --git a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbQueryBuilder.cs b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbQueryBuilder.cs
index 924731d01..12baaf7a0 100644
--- a/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbQueryBuilder.cs
+++ b/Src/Asp.NetCore2/SqlSugar.MongoDbCore/MongoDb/SqlBuilder/MongoDbQueryBuilder.cs
@@ -64,7 +64,7 @@ namespace SqlSugar.MongoDb
                     trimmed = trimmed.Substring(5).TrimStart();
                 else if (trimmed.StartsWith("AND", StringComparison.OrdinalIgnoreCase))
                     trimmed = trimmed.Substring(3).TrimStart();
-                if (IsFieldNameJson(trimmed))
+                if (MongoDbExpTools.IsFieldNameJson(trimmed))
                 {
                     var outerDoc = BsonDocument.Parse(trimmed);
                     trimmed = outerDoc["fieldName"].AsString;
@@ -135,6 +135,11 @@ namespace SqlSugar.MongoDb
                     resolveType=ResolveExpressType.SelectSingle,
                     queryBuilder=this
                 });
+                if (MongoDbExpTools.IsFieldNameJson(dos))
+                {
+                    dos["fieldName"] = "$"+ dos["fieldName"];
+                    dos.Add(new BsonElement("_id", "0"));
+                } 
                 var json = dos.ToJson(UtilMethods.GetJsonWriterSettings());
                 operations.Add($"{{\"$project\": {json} }}"); 
             }
@@ -200,13 +205,7 @@ namespace SqlSugar.MongoDb
             sb.Append("]");
 
             return sb.ToString();
-        }
-
-        private bool IsFieldNameJson(string trimmed)
-        {
-            return trimmed.StartsWith("{ \"fieldName\" : ");
-        }
-
+        } 
         public override string ToCountSql(string sql)
         {
             sql=sql.TrimEnd(']');