With the increasing development of biomass energy industry in both the world and China, it is significant to research on the contract design about biomass energy raw materials. In this paper, a two-stage supply chain under the returns policy contract mechanism is established firstly. It concerns the rife model of “base + famers” in China, which is based on economics and game theory. Secondly, the optimum order quantity of the leading part, base, is taken into major consideration so as to achieve the coordination of the supply chain, under the condition of different risk preference. Finally, a numerical analysis is provided to help conclude an optimal coordination strategy and ensure the effectiveness of the strategy.