Abstract: In this paper the effects of F^- ion in H₂SO₄ solution on the properties of surface film on Pb,Pb-Sb electrodes have been studied by cyclic potential scanning and X-ray diffrac-tion methods. It has bcen found that in the presence of F^- ion the peak potential of reduc-tion of PbO₂ on Pb-Sb electrode shifts to negative direction markedly and the discharge capacity of PbO₂ decreases rapidly with the number of scanning cycles. On the contrary,the discharge capacity is found to be increased on the Pb-Sb electrode. F^- ion helps the formation of basic PbSO₄ on both Pb and Pb-Sb electrodes, but α-PbO₂ on Pb-Sb electro-de only.