The kinetics of thermal decomposition of 2,4-bis(dimethylamino)-6-trinitromethyl-1,3,5-triazine has been studied in melt and in a dilute solution of dinonyl phthalate by manometric and gravimetric methods. The reaction has proven to be self-accelerated. The additives of N-phenylmorpholine significantly have accelerated the decomposition. A conclusion has been drawn that the dimethylamine substituents in the molecule of the initial substance are directly involved in a rate-limiting step of the reaction. Compared to the reaction in the melt, the reaction in a dilute solution has been much slower (which is not typical of the thermal decomposition of nitro compounds). This result is explained by the fact that some of the rate-limiting steps of the process are bimolecular. This is confirmed by the values of the activation parameters for the initial steps of thermal decomposition.