<p>This paper investigates the role of power structure and platform mode in determining the optimal pricing and carbon emission level in a low-carbon e-commerce closed-loop supply chain, where the manufacturer realizes the carbon emission reduction through green technology and the online platform engaged in both sales and recycling activities adopts agent or reselling mode. By comparing different situations, the results suggest that the Vertical Nash power structure benefits both the customers and the environment, the manufacturer Stackelberg power structure benefits the manufacturer and the platform Stackelberg power structure benefits the online platform. If the commission rate is low (high), the agent (reselling) platform mode benefits the customers and the environment. If the commission rate is low or high (moderate), the agent (reselling) platform mode benefits the manufacturer and the reselling (agent) platform mode benefits the online platform. Finally, the agent platform mode cannot coordinate the e-commerce closed-loop supply chain, while the reselling platform mode can through a two-part tariff contract.</p>