Dry reforming of methane to synthesis gas was studied over Ni-based catalysts. Compared to Ni/-Al2O3, the Ni/MgO--Al2O3 and Ni/MgAl2O4 catalysts exhibit higher activity and better stability using a stoichiometric feed ratio (1:1). The MgAl2O4 spinel layer in Ni/MgO--Al2O3 can effectively suppress the phase transformation to form NiAl2O4 spinel phases and can stabilize the Ni tiny crystal- lites, to which the good stability of the catalyst contributes. The application of magnesium aluminate spinel (MgAl2O4) prepared by the co-precipitation method as a support of Ni catalysts can give a high active catalytic system with excellent stability under reaction conditions. The high sintering-resistance ability and low acidity of MgAl2O4 compared to -Al2O3 and the interactions between Ni and MgAl2O4 might be responsible for its high activity and resistant to coking and sintering, because it can produce a highly dispersed active Ni species. © 2004 Elsevier B.V. All rights reserved.