Abstract: Since 2000, the county-level urbanization in China has been significantly improved nationwide. Based on data from the three national censuses conducted in 2000, 2010, and 2020, this study employs spatial analysis and regression modeling to describe the temporal and spatial distribution patterns of county-level urbanization and to analyze the main influencing factors. The study reveals the following: 1) From 2000 to 2020, the regional gap in county-level urbanization has gradually narrowed, with internal differences within the eastern, central, western, and northeastern regions being higher than differences between regions. 2) The overall development of county-level urbanization has undergone a two-stage transformation, shifting from high-speed growth led by the eastern region to accelerated catching-up in central and western regions, while the development of counties in the northeastern region has been relatively slow; the regional difference pattern has evolved from 'the northeast leads, the east follows, and the central and western regions remain at a low level' in 2000 to 'the east leads, the central region catches up with the northeast, and the west lags behind' in 2020. 3) The impact of per capita GDP, industrial structure, public service level, talent resources, and geographic positioning on the county-level urbanization rate is relatively significant. However, these factors exhibit spatial dependence, and their explanatory power varies across different regions of China.