Abstract: The parabolic point focusing thruster model was adopted as research object. The development process of flow field of air-breathing nanosecond laser propulsion with pulse repetition frequency of 2-50 Hz was numerically simulated, and the Effect of nanosecond laser pulse number and pulse repetition frequency on performance of laser propulsion was analyzed. The results indicate that with the increase of pulse number, the average impulse coupling coefficient decreased due to the reducing air density and increasing temperature. The average impulse coupling coefficient with nanosecond laser is significantly higher than that with microsecond laser, though. With the same pulse number, when the pulse repetition frequency increased, the flow field had less time to recover, leading to the decreasing average impulse coupling coefficient, and the decreasing trend is much more clear in pulse repetition frequency of f10 Hz than in f10 Hz.