In order to solve the problem that the pH value of polishing slurry on silicon substrate wafer is slowly decreasing with the increase of service time and poor buffering ability, and that the domestic nano-silica hydrosol has a large gap with the international level, the work aims to explore the effects of different proportioning formulas on polishing rate, service life of polishing slurry and surface roughness under the same pH value and optimize the polishing slurry for silicon wafer to meet the development requirements of semiconductor industry.