Reactive fragment enhances lethality by incorporating the defeat mechanisms of kinetic energy and chemical energy into a unitary damage unit.Combined studies on the behavior of reactive fragment initiating covered explosive are performed theoretically and experimentally.The results indicate that the response of the covered explosive subjected to reactive fragment is not consistent with the classical shock initiation model.When impacting and penetrating into the covered explosive,the reactive fragment releases great amounts of thermo-chemical energy up to 5.68 times of its kinetic energy into the explosive due to violent chemical reactions.This impact-induced chemical energy release behavior of the reactive fragment significantly enhances the initiation capability and damage effects on the covered explosive.