Effects of fluorination treatment on electrochemical properties of La0.67Mg0.33Ni2.25Co0.75 hydrogen storage alloy were investigated, using scanning electron microscopy, charge and discharge testing, linear polarization and potential-step measurement. The results show that cycling stability is improved by fluorination treatment. The cycling capacity retention rate S50 increases greatly after fluorination treatment. Moreover, fluorination treatment contributes to an increase in exchange current density, a decrease in charge- transfer resistance and the facility of hydrogen diffusion within the bulk alloy, leading to an obvious improvement on high rate dischargeability (HRD).