The Five Second Explosion Point (5 SEP) tests and the SEM detections in this research showed that the HMX crystals and the HMX based explosives treated under different conditions can possess different thermal sensitivities That is to say higher impurity smaller granularity and worse integrity of HMX crystals can make them more thermally sensitive The addition of metal or metal oxide particles, especially nanoparticles to HMX can also enhance its thermal sensitivity Meanwhile, coating of HMX crystals with polymers to form perfect PBX and to keep them undamaged are helpful to decrease their thermal sensitivity Furthermore, the thermal sensitivity of temperature aged HMX changes differently in terms of the integrity of its particles Therefore, it can be concluded that conditions which increase the surface energy of HMX crystals or which make the HMX molecules more active to decompose at lower temperature will increase the thermal sensitivity of HMX Additionally the variation in the thermal sensitivity of HMX treated under different conditions F generally more temperate than that of its mechanical sensitivity