Abstract: A brief description is made of the safety status of water reservoirs, the hazards of defective and dangerous reservoirs and the rehabilitation works conducted during different periods in China. The characteristics and causes of main diseases and defects of defective and dangerous reservoirs are reviewed in terms of the safety in flood prevention, dam seepage flow, structure and earthquake protection. Relevant rehabilitation methods and main technical points are discussed with respect to various defects on the basis of summarizing the rehabilitation experience for defective and dangerous reservoirs. It is of guiding significance in the on-going works of consolidating defective and dangerous reservoirs in China.