Abstract: In order to improve the nuclear safety and equipment availability,this paper explores a way to gain maximum maintenance efficiency in terms of maintenance cost and capability factor.Firstly the plant system and equipment types are analyzed,and an optimal method for the control of risk,quality and cost are discussed A scheme to establish the optimization methodology and knowledge accumulation platform is put forward,considering the schedule optimization for periodic maintenances in Daya Bay nuclear power station and Ling’ao nuclear power station.