This paper studies the optimal decision of green investment in the supply chain of agricultural products composed of a risk-averse farmer and a risk-neutral retailer under centralized and decentralized decision-making. Two types of cost-sharing contracts are considered, one is the general cost-sharing contract and the other is the cost-sharing contract under the bargaining game between two parties considering the bargaining power. At the same time, the influence of risk aversion and bargaining power on relevant decision-making variables are compared. Research conclusions show that in the decentralized supply chain, risk aversion is negatively correlated with the green investment level, while in the two types cost-sharing contracts, risk aversion is positively correlated with the green investment level. Both contracts are beneficial to the improvement of the green investment level and expected utility of the supply chain. In the cost-sharing contract under the bargaining game, cost-sharing ratio and green investment level are positively correlated with bargaining power and risk aversion, respectively; the green investment level of the supply chain can be higher than that of the centralized supply chain under certain conditions; under other certain conditions, the expected utility and the green investment level of the supply chain can be higher than the corresponding value in the general cost-sharing contract. The capital cost coefficient has a negative effect on the green investment level and expected utility of the supply chain.