Dynamic Vacuum Stability Test (DVST) method was used to study the thermal decomposition process of RDX. Through fitting the data obtained from DVST, the decomposition reaction of RDX in the nonisothermal stage follows the AvramiErofeyev equation under the test conditions. The activation energy Ea is 174.10 kJ·mol-¹, and lnA is 34.45. The decomposition reaction of RDX in the isothermal stage follows the AntiJander equation, and the constant of reaction rate is 1.63×10-⁵s-¹.The final amount of evolving gases of the decomposition is 0.10 mL·g-¹. The results indicate that the DVST can record and describe the whole process of the decomposition with the parameters of pressure and temperature of sample .The terminal results of DVST method is similar to that with VST, and logical kinetics parameters were obtained through the DVST method. These data can be used for characterizing thermal stability, compatibility, and storage life and decomposition mechanisms of RDX.