Laser propulsion is a new concept technique of propulsion and will have important application in future space technology. In this paper, the analytic formulas for the impulse and momentum coupling coefficient based on point explosion theory have been derived by considering the restraint of the reflector. In the numerical study, a new method that combining the self‐similarity solution for point‐explosion at the first stage and the high resolution PPM mesh at the second stage, has been applied to calculate the high‐temperature plasma flow field generated by the focused laser beam. The simulated results show that the efficiency of laser propulsion, such as thrust, total impulse, momentum coupling coefficient etc are strongly related to the geometry of the reflector and the power of the input laser beam. © 2004 American Institute of Physics