针对背部支撑方式的平背形反射镜，提出了一种确定主镜最佳背部支撑位置的优化计算方法。利用ANSYS软件中的APDL语言建立了主镜的参数化模型。利用有限元法，以主反射镜光轴垂直时自重作用下的镜面最大变形量为目标函数，以相同工况下一阶自振频率为约束条件，对背部支撑点位置的相关参数和中心镜厚进行了优化分析，得到了满足镜面面型误差要求的最佳背部支撑位置及中心镜厚。

For the primary mirror of flat rear surface,a method of finding the optimal backside support position of the primary mirror is put forward. Using the APDL language of the engineering analysis software ANSYS,a parameter structure model of the primary mirror is built. By means of Finite Element Method,the maximum deformation of the surface of primary mirror under the gravity is converted to object function,the first model frequency is assigned to state variable,center height of primary mirror and some position dimension of backside support is converted to design variables,thus center height and optimal position satisfying the wave front error is gained by means of the optimum design method.