In this study, Ni/NiO catalyst has been demonstrated to enhance the hydrogen storage performance of MgH2. The dehydrogenation of MgH2+10wt% Ni/NiO started at approximately 180°C , achieving 5.83 wt% of dehydrogenation within 10 minutes at 300°C. Completely dehydrogenated MgH2 began to rehydrogenate at about 50°C, absorbing about 4.56 wt% of hydrogen in 10 minutes at 150°C. In addition, the activation energies of dehydrogenation and rehydrogenation of MgH2+10wt% Ni/NiO were 87.21 and 34.84 kJ/mol. During the dehydrogenation/rehydrogenation cycle, Mg2Ni/Mg2NiH4 could promote the diffusion of hydrogen, thus enhancing the hydrogen storage performance of Mg/MgH2.