Hydrogen storage properties of Mg-50 vol.%V7.4Zr7.4Ti7.4Ni composite prepared by spark plasma sintering were investigated based on the PCT measurements, kinetics and DSC estimations and microstructure observations. The results showed that the composite consisted of Mg phase and V-based solid solution, with a small amount of sintering phase at their interface, and could absorb and desorb hydrogen at 303 K and 573 K, with a maximum hydrogen storage capacity of 3.05 wt.% and 2.55 wt.%, respectively. At 573 K it was found that the Mg phase was the basis for the hydrogen absorption/desorption, but with the combination of the V-based solid solution its kinetics was greatly improved, and its hydrogen desorption temperature decreased by about 117 K, which made it possible for hydrogen desorption of Mg phase at 573 K. Meanwhile the sintering phase was considered to be a key factor in improving hydriding properties of the Mg phase, which might act as a catalyst and offer preferable paths for hydrogen diffusion from V-based solid solution to the Mg phase. (C) 2008 Published by Elsevier Ltd on behalf of International Association for Hydrogen Energy.