Abstract: Consider a kind of supply chain system consisting of one manufacturer,one retailer and a group of consumers. Aconsumer strategic returns model involving in consumer individual decisions is formulated,in which the optimal price,ordering quantities as well as returns policies are given under the service-level constraint. Next,since the two-sides-marginalization exists in the decentralized supply chain,three contracts,that is,traditional buy-back contract,differentiated buyback contract and sale-rebate contract are designed to coordinate the supply chain and their coordinat ion mechanisms are further discussed. Results show that the traditional buy-back contract and sale-rebate contract cannotattain the supply chain coordination,while the rest can realize the supply chain coordination.Finally,the impacts of the service-level constraint on supply chain's profits and the effect of differentiated buy-back contract were analyzed by numerical analysis.

Key words: consumers.returns, service-level constraint, contract, supply chain coordination