diff --git a/modules/openiddict/src/Volo.Abp.OpenIddict.Domain/Volo/Abp/OpenIddict/AbpOpenIddictStoreOptions.cs b/modules/openiddict/src/Volo.Abp.OpenIddict.Domain/Volo/Abp/OpenIddict/AbpOpenIddictStoreOptions.cs
index 5a4817a0f0..43343da9b8 100644
--- a/modules/openiddict/src/Volo.Abp.OpenIddict.Domain/Volo/Abp/OpenIddict/AbpOpenIddictStoreOptions.cs
+++ b/modules/openiddict/src/Volo.Abp.OpenIddict.Domain/Volo/Abp/OpenIddict/AbpOpenIddictStoreOptions.cs
@@ -4,7 +4,7 @@ namespace Volo.Abp.OpenIddict;
 
 public class AbpOpenIddictStoreOptions
 {
-    public IsolationLevel DefaultIsolationLevel { get; set; }
+    public IsolationLevel? DefaultIsolationLevel { get; set; }
 
     public AbpOpenIddictStoreOptions()
     {