<p>In order to examine the evolving patterns of road network density across China and their relationship to urbanization and regional connectivity, this study explores the spatio-temporal changes in China’s road network by employing kernel density estimation (KDE) on OpenStreetMap (OSM) data from 2014 to 2021. The results show the following key findings: (1) from 2014 to 2021, the kernel density of the OSM road network in China showed significant growth, with the maximum density increasing from 1.98 in 2014 to 2.89 in 2021, reflecting a 46.46% overall expansion. (2) The road network expansion displayed a clear north–south divide along the Hu Huanyong Line. Regions south of the Hu Huanyong Line experienced faster road network growth, while regions to the north saw slower development. (3) Significant variations in kernel density are particularly evident in four major urban agglomerations: the Chengdu-Chongqing, Beijing-Tianjin-Hebei-Zhengzhou, Guangdong-Hong Kong-Macao Greater Bay Area, and Yangtze River Delta urban agglomerations; these regions exhibited the most rapid growth in road density. (4) Northern regions displayed slower and more modest road network growth. Conversely, southern regions exhibited rapid growth and stronger inter-city connectivity. The southern road networks are denser and show improved connectivity, with notable developments in the Greater Bay Area and Yangtze River Delta. (5) The rapid development of each urban agglomeration is inseparable from the guidance and support provided by national policies.</p>