Measuring the collaboration of the sustainable supply chain of water diversion projects is of great significance to the sustainable operation of the project. To achieve this, it needs to develop a scientific and reasonable collaboration measurement method. Given the economic, environmental and social benefits of water diversion projects, and based on the theory of the sustainable supply chain, an order parameter index system for collaboration measurement was constructed in this study. The Dematel and Analytic Network Process methods were used to compute the local and global weights of each order parameter. A total of 161 valid questionnaires were collected from residents along the South-to-North Water Diversion Project Middle Route to measure its collaboration from 2018 to 2020. Results showed that the orderliness of the four flow subsystems of the South-to-North Water Diversion Project Middle Route increases year by year. Compared with the other three flow subsystems, the knowledge flow subsystem has a lower level of orderliness, suggesting that communication and exchanges among people along the route should be strengthened. Such findings can help identify the weak link in the collaborative management of the sustainable supply chain of water diversion projects and improve it in a targeted manner.