Abstract: In order to improve the economic benefits of the biomass-solar complementary heating system, optimization design on the economical efficiency is necessary. In this paper, a design scheme of biomass-solar complementary heating system was put forward. The economic analysis model on this system was set up. A linear programming method was used to optimize the scheme .The system was optimized taking a 200m2 building in Beijing for example. The results showed that the established economic analysis model was available, in which the price of the solar collectors, biomass pellet fuel, heat storage tank and the biomass pellet burner effected on the optimization results of the various parts parameters in the system, and the degree of influence decreased systematically. It can provide areference for the design of biomass - solar complementary heating system in the future.