The invention discloses a novel turnover device of a rear door of a dumper. The turnover device structurally comprises a dumper frame, moving wheels, lifting cylinders, a dumper carriage, clamping pins, the dumper rear door and a rear door turnover device body, wherein the moving wheels are evenly connected with the surface of the lower end of the dumper frame, the upper ends and the lower ends ofthe lifting cylinders are connected with the dumper frame and the dumper carriage respectively, the upper surface of the other end of the dumper carriage is movably connected with the upper surface of one end of the dumper rear door through the clamping pins, and the rear door turnover device body is connected to the lower surface of the other end of the dumper carriage. The parts are mutually combined, the novel turnover device of the rear door of the dumper can automatically control the dumper carriage to carry out unloading during use; meanwhile, the service life of equipment can be effectively prolonged, the situation that the equipment deforms due to long-time use and accordingly the unloading efficiency is affected is avoided, and the practicability is high.