Thermal deformation of antenna structure, caused by the harsh high and low temperature environment that satellite antenna experienced in orbit, is the main cause of the decline in electrical performance of high precision reflector. Aiming at this problem, an optimal design scheme of high precision reflector with low thermal deformation is proposed. Firstly, factors influencing the thermal deformation were analyzed from the reflector itself and the back ribs respects, and it is concluded that the honeycomb joints of reflector should be less and be symmetrically distributed, and ribs, made of honeycomb sandwich plate, with symmetrical structure and quasi-homogeneity carbon fiber layer have minor thermal deformation. Then the influence of the connection form between reflector and rib on the thermal deformation was analyzed, and the connection scheme with low thermal deformation was obtained. The optimal design scheme presented in this paper has an important reference for the same type of high precision reflector.