The decomposition mechanism of RDX crystal is widely investigated in abundance by experiments and computational simulations. Wight and Botcher explored the initial products of RDX pyrolysis by FTIR spectrum; they found NO and N2O4 are the main gas-phase products in the initial stage, illustrating that the N-N bond scission is the first step in the thermal decomposition of RDX crystal. Zhao et al. studied the infrared multiphoton dissociation (IRMPD) of RDX in a molecular beam using time-of-flight velocity spectra (TOFVS). They detected the major products from laser photolysis (mass range from 22 to 120 amu). It was concluded that the dominant channel in the RDX decomposition is a concerted symmetric triple fission of the ring in RDX. Khichar et al. conducted thermal analysis on RDX using a coupled TGA/DSC-FTIR system. N2O, NO2, CH2O, NO, HCN, CO2, CO, and H2O were identified as the major decomposition products. The combustion characteristics of RDX crystal were studied by Yan et al. with optical diagnosis methods. The reactions of NO and HCN (the products from RDX decomposition) dominate the heat release in the flame, which are further converted to N2, H2O, and CO in the downstream flame. Although many efforts are made to understand the thermal decomposition of RDX, the overall chemical mechanism during thermolysis remains obscure due to the ultrafast and complex reactions involved, which can hardly be captured in experiments.