To increase polishing efficiency and improve surface quality of silicon, electrochemical measurements were used to study the influence of polarization potential on passivation of silicon wafer, based on which tribo-electrochemical tests were done to investigate the effect of polarization potential on friction and material removal. Results show that the passivation film with better corrosion inhibition effect can be obtained under anode polarization potential of 1 V in alkaline CeO₂ polishing liquid. A higher polarization would destroy the passivation film, while a lower polarization would suppress the formation of it. Moreover, the passivation film on silicon wafer can increase surface friction coefficient as well as material removal rate.