Abstract: The supported Ni-based catalysts were prepared by impregnation method. Effects of different supports (SiO₂, ZrO₂, CeO₂, Al₂O₃ and Al₂O₃-CeO₂) and water vapour on catalyst microstructure and their performance in biomass pyrolysis gas methanation were investigated. The results indicated that CO conversion increased gradually, and the CH₄ selectivity increased firstly, and then decreased with the increase of adding water vapor amount. Compared to SiO₂, ZrO₂ and CeO₂, Al₂O₃ presented higher BET surface area and Ni metal dispersion, which promoted the activity and selectivity for biomass pyrolysis gas methanation. Furthermore, the Al₂O₃-CeO₂ modified Ni-based catalyst showed more nickel metal loading and active metal dispersion comparing to the Ni-Al₂O₃ catalyst, exhibiting more excellent methanation performances at lower temperature. CO conversion reached 97%, and CH₄ growth rate reached 110% over the Ni-Al₂O₃-CeO₂ catalyst at 300 ℃.