The high-quality development of water conservancy is the concrete embodiment of the modernization of water conservancy in the new era of China, and it is also of great significance to the promotion of the high-quality development of national economy. According to the interpretation of the concept and connotation of high-quality development of water conservancy, the discriminant criteria are formulated from five aspects: guaranteeing water security with high standards, supporting economic development efficiently, satisfying people’s happiness highly, maintaining ecological health highly, and promoting water culture with high requirements. Based on the concept, connotation and criteria, the evaluation index system of high-quality development of water conservancy is constructed according to the three-layer structure of “target-criterion-index”, and the “high-quality development index of water conservancy”(HQDI) is introduced to quantitatively characterize the state of high-quality development of water conservancy. Finally, the evaluation system is applied to the study of 31 provincial administrative regions in the mainland of China. The results show that the high-quality development index of water conservancy in most regions is at a high level, whereas that in the northwest areas is relatively underdeveloped, and that in coastal areas is higher than that in inland areas as a whole.