Abstract: Digital twin water conservancy includes 3 major categories: digital twin hydraulic engineering, digital twin basins and digital twin water network.The main research content includes 6 relationships: digital twin-hydraulic engineering, digital twin-basins, a digital twin-water network, water network-basins, water network-hydraulic engineering, and basins-hydraulic engineering.Among them, digital twin hydraulic engineering is the key to realizing digital twin basins, and digital twin hydraulic engineering and digital twin basins are the prerequisites for realizing digital twin water networks.I analyzed and summarized the basic connotation and core elements of digital twin water conservancy and the relationship with smart water conservancy.The main challenge facing the current digital twin water conservancy construction was the lack of water information models, data fusion and service standards, the low level of intelligence process of professional models, the insufficiency of intelligent gene injection, the lack of breadth and depth of twin application scenarios.Based on these, I proposed several application scenarios such as digital twin empowerment for full-dimensional construction of a national water network, multi-objective joint scheduling in basins, and hydraulic engineering life-cycle construction, to provide construction ideas for digital twin water conservancy.