The invention discloses a railway waste truck disassembling method which comprises the following steps that 1, an RGV is operated to a previous cutting station, a telescopic hook mechanism extends out of a main truck body and is connected with a bottom plate of a railway waste truck, and the RGV drags materials to the next disassembling station; 2, the RGV moves to the position below the bottom plate through a shrinkage material hydraulic jacking platform, and a bogie is pushed to a bogie discharging station through a push rod mechanism; 3, the RGV returns to the position below the bottom plate, the material hydraulic jacking platform is lifted, and the bottom plate is carried to the next station; 4, when the RGV runs to the joint of a longitudinal guide rail and a transverse guide rail and stops, the truck body hydraulic jacking mechanism works, the main truck body is lifted, a longitudinal wheel set is separated from the rail, an auxiliary truck body sinks, and a transverse wheel set falls to the ground; and 5, the RGV runs along the transverse guide rail, the bottom plate is conveyed to a turnover mechanism, after the turnover mechanism fixes the bottom plate, the material hydraulic jacking mechanism shrinks, and the RGV leaves the station area. Meanwhile, vertical rail changing can be achieved, the working space is saved, and the operation efficiency is improved.