Abstract: Methane dry reforming reaction is a promising route for the valorization of both CO₂ and CH₄. However, the catalysts usually suffered from the coking deactivation and the sintering of active phase under the harsh reaction conditions. In this paper, the Mg-Al spinel support with different Mg content prepared by the solvent evaporation-induced self-assembly method was investigated. With this support, Ni/MgAl₂O₄ was used as the catalyst for methane dry reforming to syngas. XRD, BET and TEM results showed that the addition of appropriate amount of magnesium (10%−15%) was beneficial to the formation of highly stable ordered mesoporous magnesia spinel support with large specific surface area, which can confine the Ni particles in the pore structure and thus enhance the nickel dispersion and improve the resistance of coke formation under high temperature. H₂-TPR and XPS analysis indicated the addition of 10%−15% magnesium can promote the interaction between Ni and MgAl₂O₄, inhibiting the agglomeration of Ni and the coke formation with the active surface-adsorbed oxygen species. Detailed activity tests showed that Ni/MgAl₂O₄ catalysts with 10%−15% magnesium content has high CH₄ and CO₂ conversion. During the long-term test for 180 h, the Ni/15-MAO catalyst exihibited the CH₄ and CO₂ conversions of 92.6% and 92.5%, respectively. The coke deposition percentage was only 0.89% and the grain size of Ni was maintained after reaction.