diff --git a/modules/identity/src/Volo.Abp.Identity.Application/Volo/Abp/Identity/IdentityUserAppService.cs b/modules/identity/src/Volo.Abp.Identity.Application/Volo/Abp/Identity/IdentityUserAppService.cs
index 0220d2218d..f9b5a53a46 100644
--- a/modules/identity/src/Volo.Abp.Identity.Application/Volo/Abp/Identity/IdentityUserAppService.cs
+++ b/modules/identity/src/Volo.Abp.Identity.Application/Volo/Abp/Identity/IdentityUserAppService.cs
@@ -224,9 +224,9 @@ public class IdentityUserAppService : IdentityAppServiceBase, IIdentityUserAppSe
         var operatorOwnRoleSet = (await UserManager.GetRolesAsync(operatorUser)).ToHashSet(StringComparer.OrdinalIgnoreCase);
 
         var inputRoleNameSet = new HashSet<string>(inputRoleNames ?? Array.Empty<string>(), StringComparer.OrdinalIgnoreCase);
-        var keepUnmanageableRoles = targetCurrentRoleSet.Except(operatorOwnRoleSet);
+        var keepUnmanageableRoles = targetCurrentRoleSet.Except(operatorOwnRoleSet, StringComparer.OrdinalIgnoreCase);
 
-        var desiredManageableRoles = inputRoleNameSet.Intersect(operatorOwnRoleSet);
+        var desiredManageableRoles = inputRoleNameSet.Intersect(operatorOwnRoleSet, StringComparer.OrdinalIgnoreCase);
 
         return keepUnmanageableRoles
             .Concat(desiredManageableRoles)