A facile synthesis route for directly preparing Ni-based mesoporous carbon/silica composite catalysts without further reduction was synthesized successfully. The synthesis procedure was achieved by using the one-step solid–liquid grinding method with a mixture of SiO2, soybean oil, and nickel acetyl acetonate. Calcination was then performed with different temperatures to obtain the Ni-based mesoporous carbon/silica composite catalyst. All experimental steps were conducted without solvent addition. In this catalyst structure, soybean was used as the carbon source and provided a large surface area within the silica skeleton; Ni0 was used as the active metal. The active component Ni0 was formed directly during the soybean oil carbonization process. A series of Ni/SiO2–C–X catalysts (X = 400–1100, X stands for the carbonization temperature) were applied for the CO2 reforming of CH4 reaction. The unreduced Ni-based catalyst showed a better catalytic activity than that of the reduced catalyst under hydrogen atmosphere because the NiO phase was in-situ reduced by the carbonized soybean under nitrogen. The Ni/SiO2–C–500 catalyst showed stable activity and high reaction activity in the continuous CO2 reforming reaction of CH4 at atmospheric pressure.