The curing behaviour of an epoxy/nmSiO2 nanocomposites system composed of a bifunctional epoxy resin with an anhydride curing agent and nmSiO2 was investigated. Differential scanning calorimetry (DSC) was used to investigate the curing behaviour of the nanocomposites system. As for the nanocomposites system containing different amount of nmSiO2, the values of activation energy, reaction order, theoretic gelling temperature and theoretic curing temperature were evaluated by kinetic equations. And the effect of nmSiO2 on the curing reaction and the curing reaction mechanism of the system were discussed. The results showed that the curing rate of the nanocomposites system increased slightly with adaptively increasing nmSiO2 content, and the curing process is at 110°C for 1hr, 150°C for 2hr.