Is [UserAuthRole] useful?

After calling authRepo.AssignRoles(iUserAuth, new List() { “Master” });
I find UserAuthRole still empty, Could you tell me how to use UserAuthRole? What’s the purpose of UserAuthRole?

You need to set UseDistinctRoleTables = true to have Users Roles and Permissions stored in the UserAuthRole table, e.g:

container.Register<IAuthRepository>(c =>
    new OrmLiteAuthRepository(c.Resolve<IDbConnectionFactory>()) {
        UseDistinctRoleTables = true,

This is already mentioned in the Authentication docs

Get that,could you tell me the difference between two methods, which one is preferred, why should i use IManageRoles

There is no difference other than the default blobs the Roles/Permissions with the User (as done with each of the other NoSql AuthRepo’s) where as UseDistinctRoleTables=true stores them in separate RDBMS tables.

There is no preference, it’s up to you as to which one you prefer, this option was added because others had requested it.