Abstract: Until now, the concrete dams which are built in 1950s and 1960s have been in operation for more than 40 years. The durability of dams are affected by factors such as foundation deterioration, erosion and abrasion, freeze-thaw and frost heave, surface carbonation, leakage, corrosion, sulfate attack, cracks, loss of hydraulic machinery, reservoir sedimentation etc. Even worse, some dams encounter safety and stability problems as serious aging. After reinforcement and scientific operation, the dams are in normal condition now. In order to extend the service life of the dams, analysis on durability factors should be enhanced. As well, engineering control measures and appropriate adjustments to operation mode should be combined. Finally, timely elimination of major aging diseases and damage to dam durability should be carried out.