Abstract: In order to study the cooperative emission reduction strategy of dual-channel supply chain considering low carbon subsidies and low carbon publicity of retailers under carbon cap-and-trade, a dual-channel supply chain consisting of a manufacturer and a retailer is constructed. The models of centralized decision-making with carbon emission reduction subsidy and low carbon publicity, and the models of decentralized decision-making with no carbon emission reduction subsidy and no low carbon publicity cost allocation, and carbon emission reduction subsidy but no low carbon publicity cost allocation, carbon emission reduction subsidy and low carbon publicity cost allocation are respectively established in the dual-channel supply chain, and the optimal decision analyzed. It is pointed out that the coordination of dual channel supply chain can be achieved with government's carbon reduction subsidy, allocation of carbon emission reduction cost and low carbon promotion cost. The results indicate that optimal carbon reduction rate, optimal low carbon promotion level and dual channel supply chain profit are positively related to government subsidy ratio, the influence coefficient of low-carbon preference on demand, the influence coefficient of low-carbon promotion on online consumer demand, and the influence coefficient of low-carbon promotion on offline consumer demand. The optimal carbon reduction rate, optimal low carbon promotion level and dual channel supply chain profit are inversely related to the cost coefficient of low carbon promotion and carbon emission reduction. The optimal carbon emission reduction rate is positively related to carbon emission trading price, but optimal low carbon promotion level and dual channel supply chain profit are inversely to carbon emission trading price.