This paper focuses on the application of Taguchi method for optimization of SUS440 stainless steel polishing process parameters to obtain the best finish. An optimization experiment for polishing stainless steel with SiO2 was designed by Taguchi method. Surface roughness Ra is considered as criteria for optimization. Influence of parameters involving load, speed, and slurry concentration for a given workmaterial with given abrasive (material and size) are discussed, and the optimum polishing conditions are figured out. Compared with single parameter experimental results, it illustrates that the experiment design based on Taguchi method can successfully applied to determine the optimum processing conditions for SUS440 stainless steel polishing process.