Space radiator is an important part of aerospace thermal control system. In order to meet the heat dissipation and weight reduction requirements of a low-orbit satellite, an optimization strategy of fixed honeycomb plate space radiator has been proposed with the help of inverse design concept, and the root cause of space radiator performance improvement has been expounded from the perspective of macro and micro heat transfer. Taking the layout parameters of heat pipes and fluid loop as the design variables, Kriging was used to construct the surrogate model, and the scheme α and β were obtained by iterative optimization based on NSGA-II algorithm. The simulation results show that the optimization schemes improve the surface temperature uniformity by 3.09K and 4.98K respectively, and improve the heat dissipation capacity by 18.7% and 28.8% on the basis of reducing the mass by about 1/4. The on-orbit temperature level of satellite were compared and analyzed. The verification results show that the optimal design of the radiator makes the spacecraft thermal control system have greater temperature control margin and significant weight reduction advantages, which is more conducive to the development and expansion of spacecraft on-orbit tasks.