The invention discloses a polisher for workpiece flange burrs and a polishing process thereof and belongs to the technical field of a polishing device. The polisher for workpiece flange burrs, disclosed by the invention, comprises a bracket, a driving mechanism, a chassis and a self-polishing box, wherein the bracket has two plate structures vertically fixed on the chassis; the self-polishing box is erected in the middle of the bracket through a rotating shaft and is rotatably connected with the bracket; and the driving mechanism is used for supplying rotating power to the rotating shaft of the self-polishing box. The polisher can polish respective flanges through the mutual polishing of the workpieces; the irregularity of different workpieces after the self-polishing box is rotated at a specific rotating speed on the position and posture of the self-polishing box is fully utilized to correctly and comprehensively polish the workpiece flanges; and special polishing accessories are not needed, so that the purposes of low investment, low production cost and good polishing effect can be achieved.