Laser simulation shooting technology has the advantages of low cost, high safety, and strong simulation effect, which has been used in daily military training. Aiming at the problem of large far field light spot, an adaptive laser simulator for soldier training is designed in this paper. According to Mie theory, the laser power attenuation caused by atmosphere is calculated. the corresponding relationship between the distance of beam from the optical axis centroid and the optical power at this position are studied, and the corresponding beam model is established. The functional relationship between the optical power between 120~200 meters and the threshold spot diameter of the detector are analyzed, the driving circuit of the laser is designed, the adaptive control theory of the threshold spot of the laser is established, and the far-field spot is regulated based on the PWM output of STM32. Through adjusting the threshold spot diameter of the detector from large to small, the kill range of the simulator′s far-field firing is adjusted. Finally, the adaptive control system is verified through experiments, and the threshold light spot at 200 meters is adjusted to the ideal state, which solved the problem of hitting multiple people with a single shot from a distance, which improves the reliability, convenience, and practicability of the simulator.