Nickel–alumina xerogel catalysts (XNiAl) with different nickel contents (X, wt%) were prepared by a single-step sol–gel method for use in the methane production from carbon monoxide and hydrogen. The effect of nickel content on the catalytic performance of XNiAl catalysts was investigated. Conversion of CO and yield for CH₄ over XNiAl catalysts drastically increased with increasing nickel content from 20 to 40wt%, but they were almost constant at nickel content above 40wt%. This indicates that XNiAl catalysts with nickel content above 40wt% served as efficient catalysts in the methane production from carbon monoxide and hydrogen. The enhanced catalytic performance of nickel–alumina xerogel catalysts with nickel content above 40wt% was attributed to the abundant active surface nickel species caused by well-developed framework mesopores and large pore size of the catalysts. When considering the amount of nickel used for the preparation of catalyst, it is reasonable to conclude that the optimal nickel content of nickel–alumina xerogel catalyst for methanation reaction was 40wt%.