In order to improve the hydrogenation and dehydrogenation performances of the Mg2Ni-type alloys,Mg was partially substituted by La in the alloy,and melt spinning technology was used for the preparation of the Mg20-xLaxNi10(x=0,2,4,6) hydrogen storage alloys. The structures of the alloys were studied by X-ray diffraction(XRD) ,scanning electron microscopy(SEM) and high-resolution transmission electron microscopy(HRTEM) . It was found that no amorphous phase formed in the as-spun La-free alloy,but the as-spun alloys containing La held a major amorphous phase. When La content x≤2,the major phase in the as-cast alloys was Mg2Ni phase,but with further increase of La content,the major phase of the as-cast alloys changed into LaNi5+LaMg3 phase. Thermal stability of the as-spun alloys was studied by differential scanning calorimetry(DSC) ,showing that spinning rate was a negligible factor on the crystallization temperature of the amorphous phase. The hydrogen absorption and desorption kinetics of the as-cast and as-spun alloys were measured using an automatically controlled Sieverts apparatus,confirming that the hydrogen absorption and desorption capacities and kinetics of the as-cast alloys clearly increased with rising La content. For La content x=2,the as-spun alloy displayed optimal hydrogen desorption kinetics at 200 °C. In order to improve the hydrogenation and dehydrogenation performances of the Mg2Ni-type alloys, Mg was partially substituted by La in the alloy, and melt spinning technology was used for the preparation of the Mg20-xLaxNi10 (x = 0, 2, 4, 6 The structures of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It was found that amorphous phase formation in the as- spun La-free alloy, but the as-spun alloys containing La held a major amorphous phase. When La content x≤2, the major phase in the as-cast alloys was Mg2Ni phase, but with further increase of La content, the major phase of the as-cast alloys changed into LaNi5 + LaMg3 phase. Thermal stability of the as-spun alloys was studied by differential scanning calorimetry (DSC), showing that spinning rate was a negligible factor on the crystallization temperature of the amorphous phase. hydrogen absorption and desorption kineti cs of the as-cast and as-spun alloys were measured using an automatically controlled Sieverts apparatus, confirming that the hydrogen absorption and desorption capacities and kinetics of the as-cast alloys clearly increased with rising La content. For La content x = 2, the as-spun alloy displayed optimal hydrogen desorption kinetics at 200 ° C.