Abstract: To elucidate the mechanisms through which intense anthropogenic activities reshape large-scale cross-basin water networks, this study establishes a comprehensive “morphology-structure-function” evaluation system, focusing on the receiving area of the middle route of the South-to-North Water Diversion (SNWD). Employing a “point (reservoir regulation)-line (river network transmission)” analytical framework, we systematically analyse the evolutionary patterns of the water network from 1960 to 2020 and quantify its water supply potential. The results reveal three distinct developmental stages: the centralized construction phase, the plateau phase, and the SNWD-dominated phase. Throughout these periods, the water network exhibited significantly enhanced morphological complexity and topological connectivity. Furthermore, the water supply function underwent a paradigm shift from “morphological expansion and local regulation” to “structural optimization and cross-basin integration”. This research confirms that modern backbone water network engineering effectively overcomes morphological bottlenecks through precise structural reshaping, providing a critical theoretical basis for the optimal layout of large-scale water networks.