The decision-making of dams for long-term service needs to strictly meet the engineering and technical requirements, as well as considering a series of complex social, economic, environmental and ecological issues. This paper presents the general idea of the decision-making method for dams and reservoirs of long-term service, and discusses the optional life promotion measures, including reinforcement, degradation, retirement by demolition and reconstruction near the dam site. The life quality index(LQI)is introduced to evaluate the comprehensive improvements of the dam life promotion measures caused by social life quality improvements based on the calculation of dam service reliability. The decision-making criteria of dam performance promotion measures are then proposed based on LQI and the social willingness to pay. Finally, a concrete gravity dam with stability risks was taken as an example and the optimal engineering measures of performance promotion were recommended. It is suggested to operate with a 10 m reduction of the reservoir water level or with suitable dam reinforcement measures to promote the long-term service performance, consistent with engineering practice.