Based on the current state of construction and safety of earth-rockfill dams in China, in this paper, the theories, methods and technology of long term service and risk assessment of earth-rockfill dams are discussed from the aspects of internal erosion mechanisms, monitoring and diagnosis technology of hidden defects, service performance of the seepage control system, risk analysis and decommissioning demolition. It is concluded that in the future, further study should be focused on the defect detection of dams under deep water environment, the rapid detection technology of hidden danger, multi-source information fusion inference technology of long service state for earth-rockfill dams, the decision-making technology of dam decommissioning and the evolution mechanism of secondary derivative events in the impact zone of dam break. A mature earth-rockfill dam safety and risk control system in the project full life cycle should be developed to establish systematic theories and methods of protection and promotion for long-term service performance of earth-rockfill dams.