The structural design of the R-C telescope system is researched. We utilized finite element analysis in the whole structure of R-C telescope system. Finite element analysis results of modal analysis indicate that the first natural frequency of the telescope is 183.39 Hz, which is higher than 100Hz requested by the system. Finite element analysis results of the telescope with temperature load indicate that the coaxial degree of primary-mirror and sub-mirror is 1.15 μm, which is less than 0.01 mm requested by the system. The theoretical results are coincident with experimental ones, which validates the rationality of the R-C telescope’s structure.