The film of LaMg₂Ni₉ Hydrogen Storage alloy is prepared in aqueous solution. The electrochemical performance were studied by cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS) and Tafel polarization curve. Sanning electronic microscope(SEM), X-ray diffractometer(XRD) and energy distribution spectrum(EDS)were used to research the phase structure, component and composition. The results showed that the LaMg₂Ni₉ film has a crudity surface with a cracke. The alloy film obtained at 40A/dm₂, the△G_≠reaches to 47.26kJ/mol, the Hydrogen evolution current density j_o is 5.37 A/cm₂, indicating it has higher hydrogen evolution activity; the electrode adsorption degree Q is 0.091F/cm₂, indicating the film has better hydrogen storage function.