In the context of the national strategy to integrate development and security, the critical role of territorial space security in shaping a stable and sustainable border region has become increasingly important. Although studies have examined the issue of territorial space security from various perspectives, there is still a lack of systematic assessment frameworks based on the security pattern theory. Based on the security pattern theory, this study constructs a territorial space security assessment framework that includes multidimensional elements, and applies Euclidean proximity analysis and systematic control equation modelling to quantitatively assess the territorial space security of China’s land border areas and to manage them in a zonal manner. (1) The territorial spatial security along China’s land border predominantly falls within the safer zones, transitioning from a ”light alarm” to a ”no alarm” status. With the notable exception of the southwestern border area, the security of subsystems in other border regions demonstrated a fluctuating decline from 2003 to 2022. Apart from the southwest, the overall trend for these subsystems was a consistent decrease in security threats over the same period. (2) The balanced security metrics for the systems FS, SS, GRS, STS, and TS are 0.085, 0.0988, 0.1901, 0.3339, and 0.1114, respectively. Notably, STS possesses the highest security degree threshold. The variations in security zoning patterns among different regions, under various security subsystems, are markedly distinct. Therefore, it is crucial to establish territorial spatial security stabilization zones, upgrade zones, maintenance zones, and control zones. Proposing zoning optimization and control measures is imperative for achieving the modernization of national governance and Chinese-style modernization. This will provide a theoretical foundation and decision-making references for the sustainable use of territorial space and the co-ordination of security and development in border areas.