Aviation maintenance is one of the important supports for aircraft operation and a way to ensure safe flight and control operating costs of airlines. Current use of real-time online fault prognostic and health management （PHM） has been far from full-fledged in aviation maintenance， and practical data and cases are in need. This paper puts forward a concept of maintenance mode based on PHM， and then establishes the models of optimization of maintenance plan，controling unscheduled maintenance and error impact analysis. In the simulation， different parameters are input into the PHM system. The maintenance， the cost of maintenance and unscheduled maintenance events before and after the implementation of PHM are simulated， and the advantages of the PHM maintenance mode for reduction in maintenance hours，cost and control of unscheduled maintenance events are validated. The air conditioners system is selected as the verification object， and the results show that， for the single system with the ideal condition that the parameter of PHM is best， compared to the traditional preventive maintenance， the proposed approach can reduce 56% maintenance hours， save 60% maintenance cost， and avoid 88% unscheduled maintenance events based on PHM maintenance mode.