Abstract: Based on the game theory,the differential price coordination is addressed in this paper for a closed-loop supply chain with third-party collection of used products.First,the decentralized and centralized differential pricing models are established.With them,the optimal pricing strategy and the optimal profit for the members in a closed-loop supply chain are analyzed.Then,it is found that efficiency is lost in the decentralized closed-loop supply chain.Finally，it puts forward a profitsharing coordination contract to coordinate the closedloop supply chain,which makes the profit of the decentralized closed-loop supply chain equal to that of the integrated closed-loop supply chain.

Key words:  closedloop supply chain, third party collection, differential price, profitsharing