Nano octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX) was prepared by the use of pulverized machine HLG50. The size distribution was traced by the nano laser particle size analyzer, and the particle size was characterized by SEM. The contaminants were detected by the use of FT-IR, Raman spectra, XRD and ICP-AES. The thermal decomposition of nano HMX was described by the TG/DSC simultaneous thermal analyzer. The friction, impact and shock

sensitivities were tested to indicate the stability. The result shows that the diameters of the most particles are less than 100nm and the impurities in the product were absolutely few. The peak temperature of its thermal decomposition decreased a little compared with the raw materials. The friction sensitivity reduced by a large margin, particularly the impact and the shock sensitivities decreased 132.6% and 60.0%, respectively. The stability increased so much that there would be a good application. By the way, the mechanism of reduced sensitivity was discussed.