腔镜准直是多程放大光路准直中的基础，针对高功率固体激光装置多束组并行准直对腔镜准直的要求，提出一套基于衍射对称性的腔镜准直算法，可以避免腔镜准直受到图像质量的影响而导致精度偏低。在神光Ⅲ主机装置上进行了该腔镜准直算法的实验验证，实验结果表明，相对于传统算法，采用基于衍射对称性的腔镜准直算法，可以将腔镜准直精度由8 μrad提升至3.96 μrad。

Multi-pass amplification beam path alignment is based on cavity mirror alignment. To optimize multi-segmental parallel cavity mirror alignment algorithm of high power solid-state lasers, a new algorithm of multi-pass beam path cavity mirror alignment based on diffraction symmetry is proposed, and the algorithm avoids the problem of low alignment accuracy caused by image quality. The accuracy of multi-pass amplification beam path alignment is improved from 8 μrad up to 3.96 μrad. It has been verified on SG-Ⅲ facility.