The sustainable development of water resources, social economy and ecological environment (WSE) system is crucial for achieving regional prosperity, and it is necessary and urgent to improve the sustainability of WSE system. Therefore, a sustainability assessment and multi-angle diagnosis analysis of WSE system are conducted in this study. Firstly, a novel assessment indicator system is constructed based on the Driving force-Pressure-State-Impact-Ecological basis-Response-Management (DPSIERM) model. Subsequently, the TODIMSort is innovatively improved by introducing a machine learning clustering algorithm (i.e., mean shift clustering algorithm) to obtain the sustainability grade. Finally, the sustainable development of the WSE system is diagnosed by employing the standard deviation ellipse model, coupling coordination degree (CCD) model, and the obstacle degree model. To validate the practicability of the proposed comprehensive assessment method, this paper selects Shanxi Province of China as a case study area. The results indicate that from 2012 to 2021, the WSE system sustainability in all cities of Shanxi Province has significantly improved, and the spatial distribution pattern gradually shifts from a north-south direction to a northeast-southwest direction. In addition, from 2012 to 2021, the CCD of each city in Shanxi Province is generally on the rise, and it is found that there is a certain positive correlation between the sustainability of WSE system development and CCD. Furthermore, the primary obstacle factors to WSE system sustainability in Shanxi Province in 2021 are population density, per capita water resources, modulus of water resources production, and investment in environmental conservation as a percentage of GDP. Finally, some management suggestions for promoting the sustainable development of WSE system are put forward based on result analysis and discussion.
