Abstract: Under the premise that sales prices, service levels and promotion effort levels have an effect on market demand, this study focuses on a three-level supply chain of agricultural products composed of a manufacturer, a TPL service provider and a retailer, in which the manufacturer is responsible for the production of agricultural products, the TPL service provider is responsible for the cold chain transportation, preservation and distribution of agricultural products, and the retailer is responsible for the promotion of agricultural products. A Stackelberg game decision-making model of the three-level supply chain of agricultural products is established with centralized and decentralized supply chains. The influence of factors such as freshness demand elasticity and promotion effort demand elasticity on the optimal decision-making of the agricultural product supply chain system is analyzed, and the optimal decision results between centralized decision-making and non-contracted decentralized decision-making are compared. On this basis, a contract of "revenue sharing + quantity discount + cost mutual burden" is established to coordinate the supply chain system. Finally, through the sensitivity analysis of the revenue sharing coefficient and transportation prices, it is found that when the contract parameters satisfy a specific relationship, it is conducive to the good coordination of the supply chain system and the optimal Pareto improvement of profits.

Key words: service levels, promotion efforts, three-level supply chain, supply chain coordination