In order to study the blast power of RDX-based thermobaric explosive (TBE), the cylinder test with diameter 25 mm and static explosion experiment were carried out. The parameters of Jones-Wilkins-Lee (JWL) equation of state were obtained by simulating the cylinder test with ANSYS/LS-DYNA. JWL-Miller model was introduced to simulate the propagation process of shock waves of TBE. The parameters of secondary reacting rate of Aluminums powder were determined by adjusting the calculated results according to the test results. Results indicate that the parameters of shock waves from numerical simulation with modified JWL-Miller model can fit the experiments in free field with an average relative error less than±5%.