Abstract: Since the classical polishing method to polish ultra-smooth surface requests much experience form workers and each worker has different understanding on polishing time, the accurate control of polishing time decides the processing quality of ultra-smooth surface. Therefore, a series of experiments on polishing quality of an ultra-smooth surface and polishing time were designed, which was judged according to the size of a scattering facula and luminance under the condition of total reflection. Finally, the variation of the polishing quality of ultrasmooth surfaces with polishing time is presented. It is concluded that the processing quality of ultra-smooth surfaces is affected by the change of polishing time. Some techniques for the polishing process and the criteria to assess the polishing quality were summarized.