A series of xNiCeOy@SiO2 catalysts with different cerium contents were prepared by hydrothermal coprecipitation and Stöber method. The results of catalytic performance showed that 15NiCeOy@SiO2 has the best catalytic activity with the methane conversion of 81.1% and the specific activity of the catalyst (the amount of methane converted per mol Ni per minute) of 1.14. 10NiCeOy@SiO2 exhibits the highest stability, with the methane conversion remaining unchanged within 40 h. Compared with the undoped Ni@SiO2 catalyst, the enhancement of the activity can be attributed to the reduction of the Ni particle size due to the doping of Ce, which enabled more exposure of active species. Meanwhile, the oxygen vacancies originating from extrinsic defects of ceria increase the reaction rate of activated carbon and CO2, inhibit carbon deposition, and accelerate the structure stability.