Adsorption and dissociation properties of hydrogen on Ni-adsorbed and-substituted Mg17Al12 (100) surface are investigated systematically by means of the density functional theory calculations. Results show that one Ni atom prefers to adsorb on Mg-Mg bridge site of the surface with adsorption energy -4.90 eV. For substitution systems, the Mg17Al12 (100) surface doped with 3.94 wt% and 7.69 wt% of Ni are considered. It is obtained that Ni atoms tend to replace Mg atoms occupied at the subsurfaces. With the addition of Ni, the energy of atomic (molecular) hydrogen adsorption (dissociation) on the Mg17Al12 (100) surface are significantly improved. The dissociation of H-2 on the Ni-adsorbed surface is spontaneous. The mechanisms analyses based on the density functional theory are in line with the experimental results. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.