Aiming at solving the problem of R&D, promotion and pricing in the low-carbon supply chain, a differential game model is constructed. Both the products’ low-carbon degree and goodwill are used as state variables. Meanwhile, it is considered that the market demand is affected by multiple factors, including the low-carbon degree, the goodwill and the retail price. Then, the feedback equilibrium strategies under different decision situations are obtained and compared. Furthermore, the sensitivity analysis of related parameters is conducted by using the numerical simulation method. The results show that the economic performance and environment performance of the low-carbon supply chain can achieve “win-win” with the help of centralized decision. In decentralized decision, wholesale price has important but different influences on equilibrium strategies and profits. The products’ low-carbon degree trajectory is monotonic while the goodwill trajectory shows changing diversity.