In order to improve the quality and efficiency of wafer chemical mechanical polishing(CMP),the green water based slurry was prepared by CeO2/SiO2 composite abrasives with homogeneous precipitation,and the polishing performance of CeO2/SiO2 composite abrasive slurry on silicon wafer was studied by changing pH value of polishing slurry,polishing time,polishing speed and polishing pressure.The results show that the material removal rate is increased with the increasing of pH value of polishing slurry,and decreased with time within a certain polishing time.With the increasing of polishing rate and polishing pressure,the amount of material removal is increased first and then decreased.The polishing mechanism of CeO2/SiO2 composite abrasive slurry is that the soft layer easy for grinding is formed on wafer surface by CeO2/SiO2 composite abrasives due to the hydration.