The utility model relates to a shifting vehicle with adjustable supporting length and width and a shifting system used in dismantling industry of the shifting vehicle. The shifting vehicle runs on parallel rails and comprises a door type frame and rail wheels, wherein the rail wheels are fixed to the lower parts of the two sides of the door type frame; the door type frame comprises cross beams consisting of cylindrical profile steels; supporting arms are moveably arranged on the two sides of the cylindrical cross beams in a sleeving way respectively; two or more than two positioning holes are formed in the supporting arms at intervals; correspondingly, bolt holes corresponding to the positioning holes are also formed in the two sides of the cylindrical cross beams; bolt rods are moveably inserted into the positioning holes and the bolt holes. By very simple structural improvement, the length and width of the shifting vehicle can be adjusted conveniently and significantly, so that a rejected vehicle and a rejected electric appliance which are randomly received can be usually shifted and detached at any time, the number of carrying tools and the management cost are effectively reduced or saved, the phenomena of large occupation area and chaos field are avoided, and the working efficiency of detachment is improved.