Reactive material lining is an efficient damage enhancement technology that incorporates the defeat mechanisms of kinetic energy and chemical energy. The liners are fabricated by cold isostatically pressing at a pressure of 250MPa. In this paper, the formation behaviors of jet with the polymer-based reactive material liner are investigated by numerical simulation and X-ray photographs. The corresponding simulations of jet formation are presented, and the results agree well with experimental ones. They show that the reactive material liner can shape almost continuous and straight jet. Compared with the conventional copper liner, the reactive material liner can shape jet in a shorter time, but the jet break easily and lose stability due to its poor ductility. Although the penetration depth is sacrificed slightly when penetrating steel target, the reactive material liner produce a significantly enlarged hole-diameter.