Abstract: Against the backdrop of profound transformations in China’s socioeconomic development and territorial spatial patterns, elucidating the spatio-temporal evolution and driving mechanisms of urban construction land structure in resource-based areas is essential for optimizing territorial spatial allocation and promoting high-quality regional transformation. This study examines urban construction land in Shanxi Province from 2006 to 2020. The land-use dynamic degree index, information entropy model, shift-share model, and Lorenz curve are employed to characterize the spatio-temporal evolution of urban construction land structure, while Geodetector is used to compare its driving mechanisms across different stages. The results show that: ① the total area of urban construction land overall increases, whereas structural information entropy declines, and information entropy is negatively correlated with the growth rate of urban construction land; ② the spatial evenness of different land-use types varies considerably. Municipal utilities land and green space and squares show an increasing tendency toward spatial concentration, whereas residential land exhibits the most pronounced improvement in spatial evenness; ③ the competitive shift component exhibits marked spatial heterogeneity, with low-value areas occurring predominantly in coal resource-based cities and clustering along the Yellow River; ④ the degree of land-use change follows a “slow-active-slow” pattern. Cities with stronger economies maintain relatively high magnitudes of land-use change, while industrial land and municipal utilities land experience pronounced crowding-out effects and substantial declines; ⑤ population structure and economic development exert strong influences on the evolution of land structure, whereas industry-related factors exert negative effects. Moreover, interactions among factors are substantially stronger than the effects of individual factors. The findings indicate that the rational evolution of urban construction land structure depends on coordination and mutual reinforcement among different urban systems, whereas an excessive share of a single land-use type, particularly industrial land, can inhibit the orderly configuration of land uses. Therefore, promoting the sustainable development of resource-based cities and the economical and intensive use of land requires city-specific strategies and compact urban development, together with proactive optimization of human-land relationships.