To investigate the safety of explosive under thermal and impact coupling effect, a 50 kg drop hammer impact test of HMX based PBX with Φ20 mm×8 mm at 20-170 ℃ was performed by a self-designed experimental device.In the experiment, the pressure histories of explosive during the impact process was measured by pressure sensors.The impact ignition process of explosive was shot by the high-speed photography system.The impact response characteristics of PBX explosive at different temperatures were obtained.Results show that the impact safety of forming PBX explosive was closely related to the temperature, the impact safety at 82 ℃ is improved, and the impact safety at 170 ℃ becomes worse significantly.In the temperature range of 20 ℃ to 170 ℃, with increasing the temperature, the impact sensitivity of PBX first decreases and then increases gradually.This is related to the mechanical property changing of PBX explosive occurred at high temperature, and the damage caused by thermal expansion, thermal decomposition, and the phase transition occurrence of HMX and other factors.