Abstract: Through sol-gel processing, RDX/AP intermolecular explosive (IMX) with different proportion of RDX to AP have been prepared. Using TGA/DSC, the analyzing results show that the weight loss at first step and decomposition enthalpies of physical mixture are much lower than IMX. The best mass ratio of RDX and AP is 1.56, and its decomposition enthalpy reaches 2 160.6 J/g. The activation energy of the decomposition reaction of IMX is higher than that of physical mixture, which means that the thermal stability of IMX is increased. Compared with the decomposition rate constants at different temperature, the decomposition of IMX is much easier than physical mixture's at high temperature and IMX is more stable at normal temperature.