Abstract: In this paper,Monte Carlo method is used to analyze the flow field of the vacuum plume of the ablative laser thruster. Based on the principle of ablation,a theoretical model of laser thruster injection was established,and the flow field of the vacuum plume was numerically simulated. The simulation results are compared with the experimental results,and the results show that the simulation results are in good agreement with the experimental results. This paper provides a theoretical basis for plume flow field and sensitive indication pollution analysis of satellites equipped with laser thruster.