The precise identification of territorial spatial conflict (TSC) and the research on its driving mechanism are key approaches to deepen the frontier exploration of geography, also enhance spatial security control. Based on existing spatial conflict measurement methods, this paper incorporates the spatial capacity index, representing socio-economic-environmental factors, to construct a TSC measurement optimization model of “Complexity-Fragility-Stability-Capacity”. Additionally, the explanation rate of spatial conflict is proposed to verify the rationality of the measurement results of TSC. The Intensity Map model, spatial econometric model and optimal parameters-based geographical detector are employed to reveal the evolutionary trend and driving mechanism of TSC in China's land border. Finally, the regulation pathways of TSC in border regions are put forward. The results indicated that (1) From 2000 to 2020, the spatial pattern of China's land border was dominated by green ecological space, with a rapid increase in urban living space, a relatively slow growth in agricultural production space, and an intensified contraction of green ecological space. (2) The evolution of TSC in China's land border was significant, showing a strengthening trend and a continuous increase. Border spatial conflicts exhibit a trend of transitioning from low conflicts to higher conflicts. (3) The evolution of TSC in China's land border is the result of the interactive influence of multiple factors, leading to transformations, structural reorganizations, and directional changes in territorial space utilization. Therefore, establishing a “comprehensive coordination, full-line management” mechanism for border territorial spatial supervision is a crucial measure to optimize the sustainable development pattern of border regions and alleviate the conflicts.