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To improve the cracking behavior of hydrocarbon, Ni–Mo/SiO2 bimetallic catalysts were synthesized by different preparation methods (sol-gel, co-impregnation and single-impregnation) and added the additives (citric acid, polyethylene glycol and cetyltrimethylammonium bromide) based on the most suitable method above. The cracking reaction of methylcyclohexane under supercritical conditions was performed as the probe reaction to estimate the catalytic performance, and the properties of Ni–Mo/SiO2 catalyst were characterized by N2 absorption-desorption, XRD, XPS, H2-TPR, NH3-TPD, in-situ IR of NH3 desorption, HRTEM and STEM-mapping so as to study the structure-activity relationship. The catalyst synthesized via sol-gel method showed the best conversion and heat sink, being 81.8% and 3.81 MJ/kg, which was closely related to strong mutual effect between active components and SiO2 as well as strong acid sites. Besides, the introduction of additives by sol-gel method has an affirmative influence on properties of Ni–Mo/SiO2 catalysts, being that the acidity (more L and B acid sites) was modulated and organic groups interact with metal to suppress the aggregation of metal species (Ni and Mo), thereby enhancing the catalytic activity. At 750 °C, the conversion (89.3%) as well as heat sink (3.99 MJ/kg) of MCH cracking obtained an optimum over Ni–Mo/SiO2 catalyst with addition of citric acid.