Abstract: Remote sensing technology is like the "clairvoyance" of water conservancy. In recent 20 years, the subject of remote sensing technology and its application have made a lot of achievements. However, in the new stage of high quality development of water conservancy undertakings and developed rapidly spatial data analysis and mining technology, effort is needed to further make up the technical shortcomings. This paper reviews the main course of the development of water conservancy remote sensing in China, and combed the main research achievements in many aspects in recent 20 years including remote sensing application theory, flood and drought disasters monitoring and assessment, monitoring and supervision of soil and water conservation, crossborder river basin monitoring survey, water cycle processes monitoring and parameter inversion, UAV low altitude remote sensing and field monitoring experiment, etc. Combining with the national demand and technology development trend, this paper analyzed the development trend and recent key research tasks of water conservancy remote sensing subject.