ing at the small viewing angle in the laser communication system and the change of heat flux on the geostationary orbit, an optimized design scheme of baffle on the geostationary orbit is proposed by grids added in the inner walls of the laser communication system. With the primary mirror of optical antenna as an example, the secondary radiation analysis of baffle is conducted by the energy uniform distribution method. With the energy shielding ratio not higher than 3% as the constraint condition, the optimized baffle structure is obtained. The simulation results of temperature levels and temperature difference of primary and secondary mirrors of baffles after optimization show that the designed baffle can make the available communication rate increase from 81.51% to 92.17%, compared with that by the traditional cylindrical hollow baffle.