高能激光系统中，反射镜镜面热变形会使系统的输出光强和波前分布不均匀性加剧，从而导致输出光束质量的下降。建立了复杂镜面光线追迹的模型，使用Fresnel衍射公式和光线追迹的方法，研究了高能激光系统内通道不同数量22.5°反射镜对输出光束质量的影响。该方法和部分结果对高能激光系统激光器的优化设计，激光内通道冷却方式以及自适应光学校正能力设计参数的选取具有一定的参考价值。

Thermal distortion is severe on the reflectors in inner channel of high energy laser (HEL)system nowadays. The influence of thermal distortion is significant on the laser beam quality. Based on the Kirchhoff diffraction integration equation and model of ray tracing on the distorted mirrors, the influence of 22.5° mirrors in different channels on the beam quality is studied. The research method and some results in this paper are useful for the optimization of HEL system, cooling-down method of inner channel and selecting of AO parameters.