The film of LaMgNi4 alloy was prepared by constant-current electrodeposition method in an aqueous solution. The electrochemical performance, surface morphology and structure of the film were studied by cyclic voltammetry, charge-discharge cycle, SEM and XRD. The results show that as a hydrogen storage electrode, the film has good electrochemical activity with no need for an activation procedure and the capacity reached 398 mAh/g in the first cycle.