The present invention is a method of metal polishing and oxidation film process applied on a metal workpiece. The process comprises (a) providing the metallic workpiece in an electrolysis polishing liquid; (b) a temperature control device controlling a liquid temperature of the electrolysis polishing liquid; (c) a voltage supply device to exercising an operating voltage between the metallic workpiece and the electrolysis polishing liquid; (d) polishing the surface of the metallic workpiece and forming an oxidation layer by regulating the temperature control device and the voltage supply device; and (e) determining a film thickness of the oxidation layer formed on the metallic workpiece according to an operation time, wherein the film thickness is related to a roughness and a color displayed on the metallic workpiece. The metallic workpiece may be dyed together during the polishing process without adding any dyes. The present invention further provides a system of alloy oxidation film process.