The invention provides a polishing device and a polishing method. The polishing device comprises an upper disc, the upper disc comprises polishing units, a motion device, polishing solution conveyingpipes and electromagnetic valves; each polishing unit comprises a height adjusting device which can be used for adjusting the height of the polishing unit, the motion device is used for enabling the polishing units to do transverse motion and longitudinal motion, the electromagnetic valves are used for controlling the polishing solution conveying pipes to be opened or closed, and each polishing unit is provided with the independent polishing solution conveying pipe and the independent electromagnetic valve. Through the independent polishing units of the upper disc of the polishing device, independent polishing operation of all composition units of a part to be polished can be achieved, the whole polishing rate is reduced, and the Zara caused by polishing can be greatly reduced.