Abstract: With the development of circular economy, enterprises invest more in the recycling of discarded products, saving energy and materials to improve the corporate profits and fulfill social responsibility. To solve the closed-loop supply chain problem of enterprise recycling and remanufacturing, a two-tier closed-loop supply chain network, with the manufacturer recycling and the remanufacturer investing capital to improve the remanufacturing rate of recycled products, is constructed. The investment function of remanufacturing rate is established. The equilibrium theory and variational inequality theory are used to describe the decision-making behavior of the decision-maker. The minimization of emission is considered based on the maximization of profit. By using the modified projection algorithm, the optimal production decision of enterprises under different recovery standards and subsidy policies in the network is solved, and the impact of the investment efficiency of the enterprise on the equilibrium decision-making analyzed. The results show that the increase of the minimum recovery standard will reduce the environmental emissions, while the increase of the recovery subsidy will lead to the increase of the emissions. The higher the efficiency of remanufacturing investment, the more obvious the effect is.

Key words: closed-loop supply chain network, remanufacturing investment, multi-criteria decision-making, variational inequalities