In order to reduce the surface shape error of small caliber reflector in the complex environment and meet the requirements of the dynamic and static stiffness and the thermal stability, the appropriate space loading materials were selected and the lightweight design of the reflector was carried out. The flexible support component of the reflector which could be installed and adjusted was designed reasonably, and the finite element analysis of reflector component was obtained by using ANSYS. The results of analysis show that the first-order natural frequency of the component is 3 168.5 Hz;under the action of 1g gravity, the root-mean-square(RMS) value of the reflector surface shape error can reach 8.06 nm, and it can reach 5.58 nmunder the load of 10℃ temperature rise, . while under the coupled action of 1 g gravity and the load of 10℃ temperature rise, the RMS value can reach 11.05 nm.The maximum stress under the action of 10 g acceleration is 2.109 8 Mpa, and the maximum response stress of the weakest link under the action of simple harmonic excitation is 1.284 6 Mpa, all of which fully meet the design index requirements of the reflector component ,verifying the rationality of the suppor structure design.