Abstract: In order to study the coordinated development of the water resources-energy-food nexus （WEFN） in the river basin and promote its sustainable utilization, the evaluation index system of regional water resources-energy-food nexus coordinated development from three aspects of water resources, energy and food based on the relationship between them was constructed. Based on the improved distance coordinated degree model combined with TOPSIS and gray relational theory, a comprehensive coordinated development model based on the link between water resources, energy and food was proposed. Taking Taihu Lake Basin as an example to calculate the development degree and coordinated degree of the subsystems from 2007 to 2019, its coordinated development status and the coordinated development degree of WEFN were evaluated. The results showed that the coordinated development degree of WEFN in Taihu Lake Basin was in the medium development stage, and there was a trend from medium to good development stage, showing a fluctuating rise. There was a gap in the development degree, coordinated degree and coordinated development degree of water resources, energy and food subsystems in the Taihu Lake Basin, but it was basically in the medium and good stage. Among them, the degree of coordinated development of water resources subsystem was relatively high, and the coordinated degree of energy to water resources and food was the main factor affecting the coordinated development degree of the river basin. The low coordinated degree between subsystems was the reason for the weak coordinated development degree of WEFN. The breakthrough should be to improve the utilization efficiency of energy in water resources and food-related industries and optimize the structure of energy consumption to promote the coordinated development of water resources, energy and food systems.

Key words: water resources-energy-food, coordinated development degree, gray correlation, collaborative optimization, Taihu Lake Basin