Modular artillery charge system （MACS） is one of the main charge structures for large-caliber howitzers. To accurately study the interior ballistic characteristics of single modular artillery charge system and analyze the variation law of gas flow and pressure wave in the chamber， a combustion experiment platform for MACS was designed to carry out the combustion experiment of single modular artillery charge system. According to the characteristics of modular artillery charge system， the axisymmetric two-dimensional two-phase flow interior ballistic model of modular charge was constructed in different regions. Based on the high-order accurate Monotonic Upstream-centered Scheme for Conservation Laws （MUSCL）， the numerical simulation of the ignition process of single-module charge was carried out. The results show that the calculated results are in good agreement with the experimental results. The calculated maixmum errors of the pressures at different test points are less than 4%， indicating that the mathematical model established and calculation method used can describe the combustion process of single modular artillery charge system well. The results also show that before t=5.0 ms， the combustion of the module cartridge has little effect on the internal flow field of the module. The gas of main propellant can"t diffuse into the charge chamber in time due to the obstruction of the end cover of the cartridge.Only the gas of the ignition tube has a certain effect on the flow field in the chamber. The maximum pressure in the chamber during this period is about 4.3% higher than that before the right end of the fire tube is not broken. After the rupture of the cartridge， there is a pressure difference of 3.05 MPa at the boundary between the cartridge and the chamber， so that the propellant gas and solid particles flow rapidly along the axial direction to the free space of the chamber. A strong reflection of the pressure wave is formed at the bottom of the projectile. After that， the pressure wave oscillates repeatedly and gradually weakens.