Abstract: Under the background of e-commerce, e-commerce platform not only becomes a new channel for remanufacturer to recycle waste products, but also provides more convenient recycling services for consumers through the online reservation and offline recycling, which improves the efficiency of recycling and reduces the cost of recycling, thus forming an E-commerce Closed-loop Supply Chain. In recent years, with the development of low-carbon economy, remanufacturer began to explore their own "low-carbon" business strategy actively. Energy-saving and emission reduction work is carried out in the E-closed-loop supply chain to form a low-carbon E-closed-loop supply chain.
Given the low-carbon E-CLSC composed of one remanufacturer and one e-commerce platform, three decision-making models are constructed, including decentralized decision-making model without fairness concern, decentralized decision-making model considering fairness concern of e-commerce platform and joint decision-making model. Moreover, the best strategies are given for the three models, including carbon emission reduction level of the remanufacturer, the commission of e-commerce platform, the recovery price of waste products, the profits of each member of the supply chain and the whole system profit. Then, the impact of fairness concerns, consumers' awareness of low carbon products and other parameters on decision-making is analyzed. On this basis, the decisions of different models are compared and analyzed, and design a contract of "Revenue Sharing Joint Double Cost Sharing" is designed to achieve system coordination. Finally, numerical analysis is used to verify the conclusion. The research shows that:(1) the irrational fairness concern of the e-commerce platform is not only adverse to the remanufacturer and the system operation, but also against itself, and is not conducive to the cooperation of the remanufacturer and the e-commerce platform. (2) Improving the consumers' awareness of low carbon products can not only increase the number of recycled products but also increase the enthusiasm of the remanufacturer to save energy and reduce the emission. Improving the economic and environmental benefits of the system is beneficial. (3) Under the joint decision-making, the recycling price of the waste products and the carbon emission reduction level are the highest values, the e-commerce platform commissions are the lowest values, and the system profit is the highest values. The contract "Revenue Sharing Joint Double Cost Sharing" can be used to achieve system coordination.
In the contract of "Revenue Sharing Joint Double Cost Sharing", v(0 < v < 1) is assumed that the ratio of remanufacturer shares the double costs (the carbon emission reduction cost and the e-commerce platform's service cost), and the remanufacturer allows the e-commerce platform to share the proportion of its own revenue as u(0 < u < 1).
If u and v meet this condition $\left\{ {_{v = \varphi }^{u = \frac{{({l_0} + \delta h-{p_w})(1-\varphi )-\rho }}{{({l_0} + \delta h)}}}} \right.$, then the contract of "Revenue Sharing Joint Double Cost Sharing" can achieve system coordination. After coordination, the proportion of remanufacturer's channel profits is the same as that proportion of service costs undertaken by remanufacturer; the proportion of channel profits shared by e-commerce platforms is also consistent with the proportion of the e-commerce platform that bears the investment cost of carbon emission reduction.
These conclusions not only enrich and improve the theoretical basis of low-carbon E-CLSC, but also contribute to the decision-making of e-commerce platform.

Key words: e-commerce platform, fairness concern, low-carbon E-CLSC, coordination mechanism