Abstract: The La-Mg/Y-Ni composite hydrogen storage alloys with superlattice structure have the advantages of large discharge capacity, high energy density and low cost, and are important hydrogen energy storage and conversion material. At present, they are mainly used as the negative material of nickel-metal hydride batteries and anode catalyst of direct borohydride fuel cell. Superlattice La-Mg-Ni composite alloy was originally developed on the basis of La-Ni based hydrogen storage alloy by replacing La with partial Mg. Due to the low melting point and boiling point of Mg and its volatility, La-Mg-Ni alloy is difficult to be prepared by conventional melting method. At the same time, Mg in the alloy is easy to corrode and oxidize in the alkaline electrolyte, resulting in poor cycling stability of the La-Mg-Ni alloy. In order to overcome the difficulties in the preparation and the poor cycle stability of La-Mg-Ni composite alloy, the researchers also developed La-Y-Ni alloy on the basis of La-Ni based hydrogen storage alloy by replacing La with partial Y. La-Mg-Ni and La-Y-Ni alloys have very similar superlattice structures, and both can show good hydrogen storage properties. It can be seen that they belong to the same class of new superlattice structure hydrogen storage alloys. The research achievements of La-Mg/Y-Ni composite hydrogen storage alloys in the past 20 years are reviewed in this paper. The crystal structure and structure evolution of superlattice La-Mg/Y-Ni hydrogen storage alloys are introduced in this paper. Then, the effects of Mg element and Y element partial substitution of La element on the structure and properties of La-Mg/Y-Ni composite alloy are analyzed. At the same time, the effect of phase structures on the properties of La-Mg/Y-Ni composite alloys are discussed. Finally, the future challenges and development directions of superlattice La-Mg/Y-Ni composite hydrogen storage alloys are pointed out.