Abstract: A new computational method of two-phase flow interior ballistics which can be used to study the launch safety problem of propellant charge is put forward based on the DCD scheme. By rewriting the form of items about pressure in dynamics equation group of gas-solid two-phase flow,the uniform disposal of gas and solids with the same scheme are realized,and it does not need to treat them respectively. It does not need artificial filtering or numerical viscosity while using the DCD scheme,so the computational accuracy is improved. In an instance the two-phase flow interior ballistics of a howitzer is computed,the computational results agree with the test results. The influence of different fracture degree of propellant charge on launch safety is numerically simulated by the DCD scheme,in which fractured propellant charge bed is considered as a mixed charge configuration. The barrel pressure evolvement and dangerous barrel pressure,which are difficult to be reflected by the computational methods,appear in the computational results for interior ballistic of fractured propellant charge bed.