The invention discloses a La-Mg-Ni hydrogen storage material with high multiplying power performance and long cycling life. The chemical formula is La1-a-b-c-dSmaYbAcMgaNixA1yRz, wherein A is one or more of Gd, Pr and Nd, R comprises one or more of Co, Mn, Fe, Zn, Sn, Si, Cu, V, Nb, Mo, P, B, Ta, Cr, Ga and In, and the requirements that a>0, b>0, 0<a+b<=0.5, 0<c<=0.2, 0.05<=d<=0.3, 3.2<=x+y+z<=3.8, 0.05<=y<=0.3 and 0<=z<=1.0 are met. The hydrogen storage material is the La-Mg-Ni hydrogen storage material with Ce2Ni7 type phase as a main phase and has good high multiplying power performance and good cycling stability; in addition, the hydrogen storage material is low in cost and can be applied to the cathode of a nickel-metal hydride secondary battery.