Abstract: By using a Roe scheme of 2nd-order space accuracy and a MUSCLE approach, the propagation of laser-induced shock wave and the thrust generating process of axisymmetric laser thruster were simulated numerically under the air model of perfect gas and high-temperature equilibrium gas to explore the thrust generating mechanism of air-breathing laser propulsion. The result indicates that high-temperature equilibrium gas model can give a more accurate result than perfect gas model.