A type of nanocrystalline Mg Ni Cr/TiO composite was prepared by ball-milling alloy with different amounts of (0.5, 1.5, 2.5 2 0.75 0.25 2 wt%) TiO nanoparticles. The microstructures of the nanocomposites were examined by XRD and TEM. The effects of the addition of transition metal oxide TiO2 nanoparticles on the absorption and desorption properties of the nanocrystalline Mg2Ni0.75Cr0.25 alloy were investigated. The TiO2 nanoparticles could act as catalyst and the nanocomposites showed rapid absorption and desorption kinetics and good thermodynamic properties. The absorption temperatures of the nanocomposites were greatly decreased and the rates of hydriding were increased. In comparison with the nanocrystalline Mg2Ni0.75Cr0.25 alloy, the enthalpy of hydride formation for the nanocomposite was small, but the absorption capacity was reduced.