Calcination plays an important role in obtaining high-performance catalysts for heterogeneous reactions. In this work, the effect of calcination temperature on the performance of the Ni@SiO2 catalyst in the methane dry reforming reaction was investigated. The calcination temperature from 823 to 1223 K led to different sizes of Ni nanoparticles and strengths of metal-support interactions in the catalysts, which consequently affected the performance of the reforming reaction. The highest performance was neither achieved over Ni@SiO2-T (T = 823 and 923 K) catalysts with small Ni sizes and weak metal-support interactions nor gained over Ni@SiO2-T (T = 1123 and 1223 K) catalysts with big Ni sizes and strong metal-support interactions, while it was obtained over the Ni@SiO2-1023 catalyst with intermediate Ni size and intermediate metal-support interactions. The volcanic relationship between the catalytic performance and catalyst calcination temperature was assigned to both the Ni size effect and metal-support interaction that their combination significantly influenced the performance of the methane dry reforming reaction. The combination strategy may provide a possible optimization approach for other heterogeneous catalytic reactions.