Abstract: Transportation serves as the vanguard of China's modernization, with high-speed rail standing as a significant emblem of transportation modernization. The spatial flow of high-speed rail has emerged as a crucial perspective for investigating urban and regional spatial structures. Utilizing GIS spatial analysis and social network analysis methods based on national railway passenger train schedule data from 2009 to 2020, focusing on 369 administrative units in China, this study explored the spatiotemporal evolution characteristics of urban network intensity and structure, and examined the developmental disparities within and between regions. The following were the primary conclusions: (1) The intensity of urban network associations in China hadexperienced a rapid surge, with the hierarchical structure transitioning from quantity-oriented to quality-driven. Moreover, cities in central and western China were consistently ascending to the highest echelon of urban centers. (2) The network density and core-periphery structure of the urban network were in spatiotemporal heterogeneity. The urban network in coastal areas had higher correlation strength and a more hierarchical structure, and the urban network in the central region exhibited moderate correlation intensity, but operated on a larger scale. The southwest and northwest regions experienced a delayed period of high-speed rail (HSR) operation; however, their urban networks developed rapidly. Conversely, the northeastern region was the earliest HSR operation but witnessed a slower development of urban network. (3) The number of city pairs with cross-regional connections was increasing, and the intensity of cross-regional city network connections continued to increase, however was still dominated by low-level connections. The region with the highest concentration of cross-regional connections had shifted from the eastern coastal area to the middle reaches of the Yangtze River. (4) The centrality index exhibited an upward trajectory. Cities with higher degrees of centrality were predominantly concentrated along the Beijing-Shanghai, Beijing-Harbin-Beijing-Hong Kong-Macao Road and Bridge, as well as the Shanghai-Kunming passageways. Conversely, cities with higher centrality primarily consisted of regional central cities with elevated administrative levels.