In order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloy, Ni in the alloy was partially substituted by element Cu. The nanocrystalline Mg2Ni1-xCux (x=0, 0.1, 0.2, 0.3, 0.4) alloys were prepared by melt-spinning technology. The structures of the as-cast and spun alloys were analyzed by XRD, SEM and HRTEM. The hydriding and dehydriding kinetics of the alloys were measured by using an automatically controlled Sieverts apparatus. The results show that all the as-spun alloys hold a nanocrystalline structure. The substitution of Cu for Ni leads to form secondary phase Mg2Cu without changing of the major phase of Mg2Ni in the alloy, The hydrogen absorption capacity of the alloys first increases and then decreases with rising of Cu content, but the hydrogen desorption capacity of the alloys monotonously grows with increasing of Cu content. The melt spinning significantly improves the hydrogenation and dehydrogenation capacity and the kinetics of the alloys.