Mg–23.5wt%Ni–10wt%Cu and Mg–23.5wt%Ni–10wt%La alloys were prepared by melt spinning and crystallization heat-treatment. The Mg–23.5Ni–10Cu alloy (5.18wt%) after planetary ball milling has a higher hydrogen-storage capacity than the Mg–23.5Ni–10La alloy (4.98wt%) at 573K. The activated Mg–23.5Ni–10Cu alloy has a slightly lower hydriding rate in the beginning, but a higher hydriding rate after about 5min than the activated Mg–23.5Ni–10La alloy at 573K. The activated Mg–23.5Ni–10Cu alloy has a much higher dehydriding rate and a larger quantity of the decomposed hydrogen than the activated Mg–23.5Ni–10La alloy at 573K.