In the manufacturing capacity sharing platform, considering the manufacturing capacity provider’s cost misreporting behavior and the collusion behavior of the platform operator, this paper built a supply chain consisting of a platform operator, a capacity provider with surplus capacity, and a manufacturer with insufficient capacity. This paper studied the influence of the cost misreporting behavior on the supply chain members’ decisions and profits. By use of the game theory, in the scenarios including the supplier misreporting to other supply chain members and the supplier colluding with the platform, the paper analyzed the optimal pricing decision, misreporting coefficient decision, and platform’s service fee decision and further compared the profits of the supply chain and its members. The results show that the capacity provider tends to overstate the production cost for gaining more profits, which exerts negative effects on profits of other members and the supply chain. Compared with the case of misreporting to both the manufacturer with insufficient capacity and the platform, the case of colluding with platform is more favorable to the profits of the manufacturer, the platform, and the supply chain, while the supplier prefers to choose the former situation. When the sales revenue-sharing proportion, cost-sharing proportion, and service fee satisfy certain conditions, the sales revenue-sharing and cost-sharing contract can avoid the capacity provider’s cost misreporting behavior and coordinate the supply chain.