Abstract:LaNi5-xAlx (x=0, 0.25, 0.75, 1.2) alloys were prepared by vacuum induction melting. The microstructure, mechanical property, cyclic stability of hydrogen absorption/desorption and pulverization resistance of the alloys were investigated. The results demonstrate that the addition of Al element can markedly improve the stability of crystal structure and hydrogen storage capacity of the alloys; with increase of the Al content, the pulverization resistance of the alloys becomes worse at first, and then is improved; mechanical property, which is the main factor, and hydrogen storage capacity jointly influence pulverization resistance property of the alloys; in the atmosphere of ordinary high-purity hydrogen, the main reason for the capacity attenuation of the LaNi5-xAlx (x=0-1.2) alloys should be their intrinsic properties, mostly maybe the disproportionation reaction