在激光通信地面光终端的研制过程中，为保证主光学系统获得较高的成像质量和稳定的光轴指向，对次镜结构系统的动态稳定性提出了较高的要求。本文采用有限元分析方法，建立了地面光终端次镜系统的结构分析模型，分析了在施加不同偏置和预紧力情况下次镜结构系统的动态稳定性，得到了翼片偏置大小、预紧力大小与系统固有频率的曲线关系，为提高次镜结构系统的抗扭转刚度和动态稳定性提供了理论参考，对地面光终端次镜系统结构优化设计具有重要的指导意义。

In the development of the laser communication ground optical terminal, the dynamic stability of secondary mirror structure system plays an important role in ensuring the high image quality and stable optical axis orientation. By means of Finite Element Method (FEM), the dynamic stability of secondary mirror structure system has been analyzed by applying variable offset distances and preloads. The natural frequency of secondary mirror structure system increases with the offset distances, presenting a maximum around 20mm at variable preloads. While, the curvilinear relationship between natural frequency and preloads shows a monotonic increasing function. The results provide a theoretical reference to improve the torsional stiffness and the dynamic stability of secondary mirror structure system, which helps to optimize the structure design of secondary mirror system of laser communication ground optical terminal.