Abstract: The excellent atomization of the fuel in the air-breathing rotating detonation engine is extremely important to the detonation combustion. The gas-liquid combined transverse jet is one of the vital fuel injection technologies. Numerical methods were used to investigate the liquid penetration depth and auxiliary jet gas distribution. The Euler-Lagrange method was used to study the effect of different gas jets on the liquid jet. The results show that the gas jet reduces the momentum flux of the local incoming flow through the shock wave structure and increases the penetration depth of the liquid jet. Under the same incoming flow conditions, the greater the momentum flux of the gas jet, the higher the penetration depth of the liquid jet. It mainly affects the flow field area before the expansion section. The change of gas species has almost no effect on the penetration depth and atomization characteristics of liquid jet in the rear flow field.