This paper studies the optimal fresh-keeping effort level of the fresh supply chain composed of a supplier and a retailer under decentralized and centralized decision-making. Two types of the cost-sharing contract are set up: one way for retailers to provide separate cost-sharing contracts, the other for the provision suppliers and retailers to develop the game of cost-sharing contract approach. Meanwhile, the impact of the two types of cost-sharing contracts is compared on the level of overall freshness preservation efforts in the supply chain. Research conclusion shows, cost-sharing contracts benefit the overall freshness of the fresh supply chain, and can improve the profitability of suppliers, retailers and the fresh supply chain. It is most effective for the supplier and the retailer to formulate the cost-sharing contract through the game. In addition, the cost of fresh-keeping and the sensitivity of consumers' freshness play a negative and positive role in the development of the supply chain.