In view of the increasing interference of urbanization on the water resources system, the evaluation system of water resources and environment was built based on water resources, water environment and water ecology subsystems, and the urbanization quality evaluation system was built based on space, population and socio-economic subsystems. The urban-water coupling coordinated degree of 14 districts and counties in the lower reaches of the Dongjiang River Basin was calculated, and the main influencing factors of the urban-water dynamic coupling relationship were analyzed by using the grey correlation model. The results showed that from 2010 to 2020, the urbanization level of the east bank of the Greater Bay Area continued to improve, and the level of water resources environment was fluctuating upward. The urban-water coupling degree had increased significantly, from running-in stage to high-level coupling stage. The coupling coordination degree increased significantly from 2010 to 2015, and declined slightly from 2016 to 2020. The coupling coordination degree of Huangpu District, Longhua District and other urban fringe areas decreased significantly, with significant spatial differentiation. Under the high-level urban-water coupling relationship, population growth and construction land expansion were the main factors that stress the water resources environment. The shortage of water resources, the low efficiency of water use and the deterioration of water ecosystem services are the main reasons that restrict the development of urbanization.