Abstract: This study systematically analyzes the spatiotemporal evolution patterns and driving mechanisms of water use in the Pearl River Delta(PRD) urban agglomeration from 2000 to 2024, using a combination of piecewise linear regression and the Logarithmic Mean Divisia Index(LMDI) decomposition method. The results show that the total water use of the nine PRD cities exhibits a "rise then fall" trend, with 2010 as the turning point—a gradual increase from 2000 to 2010, followed by a significant decline after 2010. Industrial scale expansion and population growth are the main positive drivers of increased water use, while industrial water use efficiency improvement and irrigation area reduction are the main negative drivers of decreased water use.The water use evolution across the nine PRD cities shows significant spatial differentiation, reflecting the influence of each city's unique stage of economic development, industrial structure, demographic changes, and policy responses on water use evolution.The findings provide a scientific basis for refined regional water resources management and water use regulation in urban agglomerations.