Abstract:The diseconomies of scale nature of the producers is a common phenomenon in the economy and society, but its impact on low-carbon supply chain emission reduction and pricing decisions has received less attention. By means of game theory, this paper establishes a decision-making model of low-carbon supply chain in the mode of centralized decision-making and decentralized decision-making, and designs the revenue-sharing and cost-sharing contract to coordinate the decision-making behavior of low-carbon supply chain members under the diseconomies of scale and decentralized decision-making of producers. The results show that under centralized or decentralized decision-making mode, with the increase of the diseconomies of producers’ scale, the carbon emission reduction intensity of unit product is gradually reduced, the total profit of supply chain is gradually decreased, and the change of retail price depends on carbon coefficients of products; and there is a loss of decision-making efficiency in low-carbon supply chains under diseconomies of scale and decentralized decision of producers, which is affected by the intensities of both diseconomies the scale of producers and consumers’ carbon preferences; besides, when the revenue sharing ratio and cost sharing ratio meet certain conditions, the revenue-sharing and cost-sharing contract can realize the complete coordination of low-carbon supply chain under decentralized decision making.