A Ni-modified ceria-zirconia support with Ni impregnation at different Ni-loading catalysts for a CO2 methanation reaction was systematically studied. The corresponding structures of each catalyst were characterized by Brunauer-Emmett-Teller surface area analysis, X-ray powder diffraction, X-ray fluorescence, H-2 temperature-programmed reduction, CO2 temperature-programmed desorption, Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and thermogravimetric/differential thermal analysis. The results showed that Ni-modified Ce-Zr oxide improved the basic properties as well as the oxygen vacancies. A gradual increase in Ni loading from 15 to 45 wt % was found to increase medium-strong basic sites, and surface Ce3+ and Ni-0 species along with oxygen vacancies favor high activity. The CO2 methanation activity was related to the amount of Ni loadings where the 45Ni/Ni005CZO catalyst was reported to be the most active catalyst. This is due to the high amount of Ni surface suitable for H-2 activation and high medium basic sites to accommodate CO2 activation, leading to high catalytic activity.