Machining polishing device and polishing method thereof

The invention relates to the technical field of polishing devices, in particular to a machining polishing device which comprises a polishing mechanism used for polishing parts. The bottom box is arranged at the bottom of the polishing mechanism; the separating mechanism is arranged in the bottom box and is used for separating the part from the polishing medium; and the discharging mechanism is arranged at the bottom of the separating mechanism and used for collecting the polishing medium. According to the machining polishing device, opening and sealing of a first through opening can be controlled through vertical movement of a sealing ring in the separation mechanism, after polishing is finished, the first through opening in the bottom of the shell can be opened, so that a polishing medium sequentially passes through the first through opening, a second through opening and a third through opening to enter an inner barrel, and polishing is completed; therefore, automatic separation of the polishing medium and t