One of the key technologies for the large-scale application of CO2 sorption-enhanced methane steam reforming process for hydrogen production is the development of a composite catalyst with high catalytic and adsorption capacities. In this study, a series of NiMgAlCa composite catalysts with different MgO addition were prepared by co-precipitation method, and the influence of MgO addition on the structure of NiMgAlCa catalyst and its CO2 enhanced sorption methane steam reforming performance were investigated. It is found that MgO addition can significantly improve the activity of the NiMgAlCa composite catalysts. In the CO2 sorption-enhanced CH4/H2O reforming reaction,the as-synthesized composite catalysts can obtain a high volume fraction of H2(98.7%) and a CH4 conversion of 96.5% when MgO addition was 1%. The improved hydrogen production performance was ascribed to the addition of MgO, which endowed the composite catalyst a proper interaction between the active component Ni and the carrier in the NiMgAlCa composite catalyst. Meanwhile the higher specific surface area of the composite catalyst (42.5 m2/g) provids more active sites and enhances CO2 sorption. The small Ni particle size (13.2 nm) enhances the anti-sintering capacity of the composite catalyst, endowing the composite catalyst superior stability.