Aiming at the problems of the low maintenance efficiency of multi-component series system and the low profit of suppliers, considering the economic correlation between components, a maintenance strategy model for multi-component system based on performance-based contract was proposed. First, Weibull distribution was used to describe the service life law of each component in the system, and different maintenance strategies were implemented by judging the relationship between the usage of each component, the preventive maintenance threshold and the opportunistic maintenance threshold. Second, the probability of each maintenance activity and the corresponding number of maintenances were calculated in the unit renewal cycle, and a maintenance strategy model for multi-component system based on performance-based contract was established with the preventive maintenance threshold and the opportunity maintenance threshold as decision variables and with the goal of maximizing the profit of suppliers. Finally, Grey Wolf Optimizer(GWO) algorithm was used to solve the proposed model. The numerical example analysis showed that compared with Genetic Algorithm(GA) and Particle Swarm Optimization(PSO) algorithm, the improved GWO algorithm had the precision improved by 22.6% and 7.6% respectively, and the profit margin of the proposed performance model was as high as 25.3% based on the linear return function, which was increased by 5.2% compared with that of the traditional cost model. The model and algorithm of multi-component system maintenance strategy optimization based on performance-based contract can effectively solve the problem of low maintenance quality and efficiency of suppliers, and provide a basis for suppliers and operators to jointly make maintenance contracts.