To improve the fill coefficient of combustion chamber pressure curve under the conditions of constant area of spout,a regenerative liquid propellant gun with a supercharged combustion chamber was presented.A zero-dimensional interior ballistic model considering both liquid and solid propellant was developed and analyzed.Utilizing structural parameters and charge conditions of some mortar,the numerical simulation was carried out by using Runge-Kutta method.Based on certain structural parameters,the numerical results show that the pressure of fuel reservoir and supercharged combustion chamber will go up at all the time in spurting course of liquid propellant,and the pressure of combustion chamber is lowest and appears an approximate plateau.The numerical results indicate that the fill coefficient of combustion chamber pressure curve can be improved by setting supercharged combustion on condition that the area of spout is constant.