T he passivatio n ef fect of pro pellant on the interior ballist ic characteristics is po orly under stood now . In this paper , using closed bomb vessels ex periment s and range shoo ting exper iment s, the passivat ion ef fect of pro pellant on the burning law s is studied, and the bur ning mathematical models of passiv ation pr opellant are establ ished; an appro ach is proposed to decide the burning characterist ic variables of passivat io n propel lant , and some calculatio n and analysis for the interior ball ist ic characteristics o f passivat io n propellant are made w ith these models. T he calculatio n result s can present the interior ballistic cy cle in gun, and there is a goo d agr eement betw een the predicted result s and ex perimental result s.