The La-Mg-Ni alloy films were prepared by a constant-voltage electrodeposition method in acetamide-urea-NaBr-KBr. The surface morphology and structure of the films were studied by SEM and XRD. The electrochemical performance was studied by Tafel and EIS. The results show that the film has smoother surface and better hydrogen storage function with the cathode potential shifting to negative direction. △G≠ and Q of the deposition layer are determined to be 22.35 kJ·mol-1 and 7.98 μF/cm2, respectively when the voltage is –1.0 V, indicating the high hydrogen evolution activity and high hydrogen capacity.