The composite 85wt.%Mg-5wt.%Ni-10wt.%Ti19Cr50V22Mn9 was successfully prepared by mechanical alloying and its hydriding/dehydriding(H/D)properties were investigated by an isovolumetric method without any activation treatment.The effect of the milling time on the structure of the composite was measured by the X-ray diffraction,microscope and mastersizer technologies.The relationship between the technology and structure and properties was carefully analyzed.The composite can absorb and desorbe 6.70 wt.% and 6.6 wt.%,respectively,within 20 min at 573 K.Its H/D kinetic mechanism was studied and the results indicated that the rate-controlling step of the H/D processes is the diffusion of hydrogen,the very good agreement between the experimental results and calculated curves by a simple new kinetic model was presented.The activation energies were calculated to be 63 kJ?mol-1 for absorption and 69 kJ?mol-1 for desorption.