Ammunitions might experience safety threats of high-temperature heating， high-speed fragment impact， and their combined effects in battlefield. In order to investigate the reaction phenomenon of insensitive explosive PBX-C04 under high-speed impact and the effects of high-temperature and booster charge on this reaction phenomenon， the insensitive explosive safety experiments under high-speed fragment impact were carried out， and the influences of high-temperature and insensitive booster charges（HNS） were considered. Based on the air overpressure， witness plate wreckage and chemical-physical analysis of remained explosives on the scene， the explosive reaction levels of PBX-C04 was assessed comprehensively， and the influences of high temperature and booster charge were studied. The results show that PBX-C04 at room temperature exhibits excellent safety characteristic under high-speed fragment impact， it merely reacted to burning when impacted by a fragment with velocity up to 1970 m·s^-1. When the booster charges of HNS was included， the reaction levels of PBX-C04 correspondingly deteriorated into deflagration. However， when heated to 200 ℃ before impact test， the high-speed impact safety of PBX-C04 equipped with booster charge deteriorated remarkably into detonation.