The main parameters which influenced Pb-Ag anode passivation during zinc electrolysis process have been investigated by Linear Scan Voltammetry.The results showed that the passivation layer of Pb-Ag anode was a mixture of semiconductor film consisting of PbO2, MnO2 and other oxides.However, the passivation process was affected by the presence of Cl-and F-.Meanwhile, it was highly advantageous to the passivation of Pb-Ag anode when the concentration of H2SO4 was 180 g/L, Mn2+ was between 3g/L and 5 g/L and F-was less than 42 g/L.The passivation process would not be affected when the concentration of Cl-was less than 13 g/L in the electrolyte without other ions.However, when both Mn2+ and Cl-existed in the electrolyte in which the ratio of Mn2+/Cl-was 8, the maximum Cl-concentration in the electrolyte could reach up to 625 g/L.