为了满足大口径、长焦距空间相机中次镜相对于主镜的位置精度要求，设计并研制了主次镜间的支撑结构，分析和试验验证了组合支撑结构的稳定性。首先，根据给定的光学系统，确定了主次镜之间采用薄壁筒和支杆组合的支撑结构形式，对比了支撑杆和薄壁筒的结构形式以及二者之间的连接方式，通过优化，完成了组合支撑结构的设计。然后，讨论了重力对支撑结构的影响，并进行了固有频率和正弦振动响应分析。最后，通过量级逐增力学试验，采用光学方法测量了主、次镜间的角度变化量，验证了支撑结构的结构稳定性。试验结果表明：主、次镜间的角度变化量<10″，组合支撑结构的一阶基频>75 Hz。这些结果满足主、次镜间角度变化量要求，具有较好的结构稳定性。

To meet the relative position request of the second mirror and the primary mirror in a large-aperture and long-focal-length space camera, a combined supporting structure between the primary mirror and the second mirror was designed and manufactured,and the stability of the combined supporting structure was confirmed through the analysis and tests. Firstly, according to the optical system，the combined supporting structure which combined a thin wall joint cylinder and a supporting bar was designed. The structure forms of supporting bar and joint cylinder were compared and their connection modes were discussed. Then，the gravity response，characteristic frequency and sinusoidal vibration responses of the supporting structure were analyzed. Finally, the supporting structure stability was validated by the mechanical tests and optical measurement. The results indicate that the angle displacement between the primary mirror and the second mirror is less than 10″ and the first-order natural frequency of supporting structure is greater than 75 Hz,which shows that the supporting structure has a better structure stability, and can satisfy the usage requirements of space cameras.