With the increasing variety of the exterior wall surface treatment method, different surface treatment methods have a great impact on the appearance of the vehicle. There is also difference in fire prevention, environmental protection, maintainability and service life. In this paper, the exterior wall surface treatment method of aluminum alloy car body of rail vehicle was analyzed, From the application status of substrate characteristics, film scheme and paint scheme, the application advantages of different surface treatments were analyzed, which provided theoretical support for the selection of exterior wall surface treatment method of rail vehicles.