Can we play XBOX 360 pro games on XBOX 360 arcade without any update or modification?

Yes, you can play Xbox 360 Pro games on an Xbox 360 Arcade without any updates or modifications, as long as the games are compatible with the console. Both systems are part of the same Xbox 360 platform, so they share the same game library. However, keep in mind that some games may require specific system updates to run properly, so you may encounter issues with games released after the last update for the Arcade model.