Frame assembly of all-terrain vehicle

The invention discloses a frame assembly of an all-terrain vehicle. The rear of a main reducing gear which is provided with a lug, and a rocker part which is provided with a lug and towing are combined into a whole through a bottom tube rear composition board, and the towing, a rear rocker and the main reducing gear are mounted, positioned and combined into a sheet metal component as possible; and simultaneously, an air filter provided with a lug is arranged on the front of a frame, and an oil tank mounting plate is arranged on the rear of the frame, so that an oil tank is positioned on the rear of the frame and the air filter is positioned on the front of the frame. The frame assembly has compact structure, optimized spacial arrangement, light weight and more reasonable mass distributionof a whole vehicle, improves welding manufacturability and reduces welding frock to reduce manufacturing cost, and well guarantees strength and rigidity of the whole vehicle through reinforcing members.