A method for manufacturing an aluminum alloy vehicle body includes the following steps: vehicle body part molding, including: profile stretch-bending and machining; vehicle body frame assembly welding, including: performing assembly welding on a lower vehicle body, left and right side panels, and front and rear roof crossbeams; outer panel manufacturing, including: manufacturing an outer panel by injection molding; and whole vehicle assembling, including: assembling interior trim parts and the outer panel to a vehicle body frame, and assembling chassis parts to the vehicle body frame. The vehicle body parts and the vehicle body frame are made of an aluminum alloy material, and the outer panel is made of a non-metallic composite material.