Mg17Al12 alloys were prepared by mechanical ball milling for systematical studying the influence of milling time on the information of Mg17Al12. In order to modify the surface performances of the alloys, 5% (mass fraction) or 10% of simple substances (Ni and Cu) were added into Mg17Al12 alloys mechanically milled for 12 h. The storage properties of the alloys were determined by P-C-T apparatus. The effects of different mass fraction simple substances on the hydrogen storage properties of the alloys were investigated. The results show that the Mg17Al12 has a slow rate of absorbing hydrogen and a long-term absorption process, the maximum reversible storage capacity reaches 4.1wt% after 1400 min which is closed to the theoretical one (4.4wt%). Cu can modify the surface performance and enhance the kinetics markedly. The alloy with 5%Cu has a hydrogen absorption of 4.07wt% at 623 K in 180 min as the alloy with 10%Cu the hydrogen absorption of 3.9wt%. Mg17Al12 modified by adding Cu and Ni has a better absorption performance, as the alloy with 5% Cu can desorb 3wt% hydrogen at 553 K. Ni can modify the surface performance and enhance the properties, too. But its effect is not obvious compared to that of Cu