Nanocrystalline LaMg12–Ni composites were prepared by ball-milling a LaMg12 alloy and Ni powders with additions of small amounts of metal oxides (TiO2, Fe3O4, La2O3 and CuO). The composites with additions of small amounts of metal oxides were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the effects of the addition of the metal oxides on the electrochemical hydrogen storage were investigated. It is demonstrated that the initial discharge capacities of the composites with additions of small amounts of metal oxides were significantly higher than that of the original composite. The additions of TiO2 and Fe3O4 as catalysts improved the electrochemical hydrogen storage properties more effective than additions of La2O3 and CuO. Analysis of the electrochemical impedance spectra (EIS) showed that the function of the metal oxides was considered to reduce the electrochemical reaction resistance as catalysts and to increase the specific surface area as impurities. However, more extensive investigation is still necessary in order to improve the cyclic stability of these materials for practical application in Ni/MH batteries.