The structure, hydrogen storage property and electrochemical characteristics of the La(0.7)Mg(0.3)Ni(4.0-x)(Al(0.5)Mo(0.5))(x) (x = 0, 0.4, 0.8) hydrogen storage alloys have been investigated. It can be found that all the La(0.7)Mg(0.3)Ni(4.0-x)(Al(0.5)Mo(0.5))(x) alloys consisted of two main crystallographic phases, namely the La(La, Mg)(2)Ni(9) phase and the LaNi(5) phase, and the lattice parameters and the cell volumes of both the La(La, Mg)(2)Ni(9) phase and the LaNi(5) phase increase with increasing Al and Mo content in the alloys. The P-C isotherms curves indicate that, with increasing x, the hydrogen storage capacity first increases and then decreases, whereas the equilibrium pressure decreases step by step. (C) 2008 Elsevier B.V. All rights reserved.