By developing markets and increasing world competition, today, companies' success is not only related to their performance but also the interaction and performance of their entire supply chain and distribution. In the supply chain strategy, operational functions, such as planning, purchasing, and financial affairs are considered all together. In the meantime, the coordination between manufacturers, distributors, and retailers is of great importance. Coordination through cooperation between distribution channels is necessary because of their potential for realizing significant profits. This study presents a mathematical model for a three-echelon supply chain. In this model, the effect of the strategy of returning goods on the amount of profit as well as on the optimal amount of wholesale-retail prices is determined. The three-echelon supply chain is represented by manufacturers, distributors, and retailers. In this study, social responsibility is considered in the model and channel coordination in this three-echelon supply chain is also considered. Hence, in addition to maximizing total profit, social responsibility is also taken into consideration. Channel coordination and optimization of the supply chain are considered in both centralized and decentralized modes. In the results, it was found that the quality of products in a consistent manner is always at a higher level than in a decentralized state. Also, it was found that if decisions are made on a coordinated basis, customers who return their goods will benefit from higher earnings than decentralized. Therefore, this model helps the firms to find out the structure, which has a better performance in terms of product quality, return policy, and social responsibility impact while reducing conflict between supply chain members. Also, through a coordinated system, firms can enhance the quality of products and return policy, which in turn improves customer satisfaction and profits.

通过开发市场和增加世界竞争，今天，公司的成功不仅与他们的业绩有关，还与整个供应链和分销的互动和业绩有关。在供应链战略中，计划、采购和财务等运营职能被综合考虑。同时，制造商、分销商和零售商之间的协调非常重要。由于分销渠道具有实现显着利润的潜力，因此必须通过分销渠道之间的合作进行协调。本研究提出了一个三级供应链的数学模型。在该模型中，确定了退货策略对利润金额以及批发零售价格最优金额的影响。三级供应链以制造商、分销商和零售商为代表。在本研究中，模型中考虑了社会责任，也考虑了该三级供应链中的渠道协调。因此，除了最大限度地提高总利润外，还考虑了社会责任。集中式和分散式两种模式都考虑了供应链的渠道协调和优化。结果发现，与分散状态相比，始终如一的产品质量始终处于较高水平。此外，还发现如果决策是在协调的基础上做出的，退货的客户将受益于比分散的更高的收益。因此，该模型有助于企业找出结构，在减少供应链成员之间的冲突的同时，在产品质量、退货政策和社会责任影响方面有更好的表现。此外，通过协调系统，公司可以提高产品质量和退货政策，从而提高客户满意度和利润。