diff --git a/src/Volo.DependencyInjection/Microsoft/Extensions/DependencyInjection/ServiceCollectionConventionalRegistrationExtensions.cs b/src/Volo.DependencyInjection/Microsoft/Extensions/DependencyInjection/ServiceCollectionConventionalRegistrationExtensions.cs
index ba8b99547f..6c1f978caf 100644
--- a/src/Volo.DependencyInjection/Microsoft/Extensions/DependencyInjection/ServiceCollectionConventionalRegistrationExtensions.cs
+++ b/src/Volo.DependencyInjection/Microsoft/Extensions/DependencyInjection/ServiceCollectionConventionalRegistrationExtensions.cs
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
 using Volo.DependencyInjection;
 using Volo.ExtensionMethods.Collections.Generic;
 
@@ -11,11 +12,11 @@ namespace Microsoft.Extensions.DependencyInjection
 
     public static class ServiceCollectionConventionalRegistrationExtensions
     {
-        private static readonly Dictionary<IServiceCollection, List<IConventionalRegistrar>> ConventionalRegistrars;
+        private static readonly ConcurrentDictionary<IServiceCollection, List<IConventionalRegistrar>> ConventionalRegistrars;
 
         static ServiceCollectionConventionalRegistrationExtensions()
         {
-            ConventionalRegistrars = new Dictionary<IServiceCollection, List<IConventionalRegistrar>>();
+            ConventionalRegistrars = new ConcurrentDictionary<IServiceCollection, List<IConventionalRegistrar>>();
         }
 
         public static IServiceCollection AddConventionalRegistrar(this IServiceCollection services, IConventionalRegistrar registrar)
@@ -31,16 +32,12 @@ namespace Microsoft.Extensions.DependencyInjection
 
         private static List<IConventionalRegistrar> GetOrCreateRegistrarList(IServiceCollection services)
         {
-            var registrars = ConventionalRegistrars.GetOrDefault(services);
-            if (registrars == null)
-            {
-                registrars = ConventionalRegistrars[services] = new List<IConventionalRegistrar>
+            return ConventionalRegistrars.GetOrAdd(
+                services,
+                () => new List<IConventionalRegistrar>
                 {
                     new DefaultConventionalRegistrar()
-                };
-            }
-
-            return registrars;
+                });
         }
     }
 }
\ No newline at end of file
diff --git a/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpConventionalDependencyInjectionExtensions_Tests.cs b/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpConventionalDependencyInjectionExtensions_Tests.cs
index adf93ecc7b..64c31b9cc5 100644
--- a/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpConventionalDependencyInjectionExtensions_Tests.cs
+++ b/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpConventionalDependencyInjectionExtensions_Tests.cs
@@ -1,4 +1,5 @@
-using Shouldly;
+using System.Linq;
+using Shouldly;
 using Volo.DependencyInjection;
 using Xunit;
 
@@ -43,16 +44,92 @@ namespace Microsoft.Extensions.DependencyInjection
             _services.ShouldContainScoped(typeof(MyScopedClass));
         }
 
+        [Fact]
+        public void Should_Register_Scoped_With_Dependency_Attribute()
+        {
+            //Act
+            _services.AddType(typeof(MyScopedClassWithDependencyAttribute));
+
+            //Assert
+            _services.ShouldContainScoped(typeof(MyScopedClassWithDependencyAttribute));
+        }
+
+        [Fact]
+        public void Dependency_Attribute_Should_Override_Interface_Lifetimes()
+        {
+            //Act
+            _services.AddType(typeof(MyScopedClassWithDependencyAttribute2));
+
+            //Assert
+            _services.ShouldContainScoped(typeof(MyScopedClassWithDependencyAttribute2));
+        }
+
         [Fact]
         public void Should_Register_For_Exposed_Services()
         {
+            //Act
             _services.AddType(typeof(MyServiceWithExposeList));
 
+            //Assert
             _services.ShouldContain(typeof(IMyService1), typeof(MyServiceWithExposeList), ServiceLifetime.Transient);
             _services.ShouldContain(typeof(IMyService2), typeof(MyServiceWithExposeList), ServiceLifetime.Transient);
             _services.ShouldNotContain(typeof(MyServiceWithExposeList));
         }
 
+        [Fact]
+        public void Should_Register_Multiple_Implementation_For_Same_Service()
+        {
+            //Act
+
+            _services.AddTypes(typeof(FirstImplOfMyService), typeof(SecondImplOfMyService));
+
+            //Assert
+
+            //Check descriptons in service collection
+            var descriptions = _services.Where(s => s.ServiceType == typeof(IMyService)).ToList();
+            descriptions.Count.ShouldBe(2);
+            descriptions[0].ImplementationType.ShouldBe(typeof(FirstImplOfMyService));
+            descriptions[1].ImplementationType.ShouldBe(typeof(SecondImplOfMyService));
+
+            //Check from service provider
+            var serviceProvider = _services.BuildServiceProvider();
+
+            //Default service should be second one
+            serviceProvider.GetRequiredService<IMyService>().ShouldBeOfType(typeof(SecondImplOfMyService));
+
+            //Should also get all services
+            var instances = serviceProvider.GetServices<IMyService>().ToList();
+            instances.Count.ShouldBe(2);
+            instances[0].ShouldBeOfType(typeof(FirstImplOfMyService));
+            instances[1].ShouldBeOfType(typeof(SecondImplOfMyService));
+        }
+
+        [Fact]
+        public void Should_Not_Register_Second_Implementation_For_Same_Service_If_Second_Is_Marked_As_TryRegister()
+        {
+            //Act
+
+            _services.AddTypes(typeof(FirstImplOfMyService), typeof(TryRegisterImplOfMyService));
+
+            //Assert
+
+            //Check descriptons in service collection
+            var descriptions = _services.Where(s => s.ServiceType == typeof(IMyService)).ToList();
+            descriptions.Count.ShouldBe(1);
+            descriptions[0].ImplementationType.ShouldBe(typeof(FirstImplOfMyService));
+
+            //Check from service provider
+            var serviceProvider = _services.BuildServiceProvider();
+
+            //Default service should be second one
+            serviceProvider.GetRequiredService<IMyService>().ShouldBeOfType(typeof(FirstImplOfMyService));
+
+            //Should also get all services
+            var instances = serviceProvider.GetServices<IMyService>().ToList();
+            instances.Count.ShouldBe(1);
+            instances[0].ShouldBeOfType(typeof(FirstImplOfMyService));
+        }
+
         [Fact]
         public void AddObjectAccessor_Test()
         {
@@ -90,6 +167,18 @@ namespace Microsoft.Extensions.DependencyInjection
 
         }
 
+        [Dependency(ServiceLifetime.Scoped)]
+        public class MyScopedClassWithDependencyAttribute
+        {
+
+        }
+
+        [Dependency(ServiceLifetime.Scoped)] //Attribute overrides interface
+        public class MyScopedClassWithDependencyAttribute2 : ITransientDependency
+        {
+
+        }
+
         public interface IMyService1
         {
             
@@ -99,13 +188,31 @@ namespace Microsoft.Extensions.DependencyInjection
         {
 
         }
-
+        
         [ExposeServices(typeof(IMyService1), typeof(IMyService2))]
         public class MyServiceWithExposeList : IMyService1, IMyService2, ITransientDependency
         {
             
         }
 
+        public interface IMyService : ITransientDependency
+        {
+            
+        }
+
+        public class FirstImplOfMyService : IMyService
+        {
+        }
+
+        public class SecondImplOfMyService : IMyService
+        {
+        }
+
+        [Dependency(TryRegister = true)]
+        public class TryRegisterImplOfMyService : IMyService
+        {
+        }
+
         public class MyEmptyClass
         {
             
diff --git a/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpDependencyInjectionSpecifications.cs b/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpDependencyInjectionSpecifications.cs
deleted file mode 100644
index 7ea2bb0f04..0000000000
--- a/test/Volo.DependencyInjection.Tests/Microsoft/Extensions/DependencyInjection/AbpDependencyInjectionSpecifications.cs
+++ /dev/null
@@ -1,19 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-using Volo.DependencyInjection;
-
-namespace Microsoft.Extensions.DependencyInjection
-{
-    public class AbpDependencyInjectionSpecifications
-    {
-        //TODO: Tests...
-
-        public class MyScopedClass : IScopedDependency
-        {
-
-        }
-
-    }
-}