Resource-based cities face complex land-use pressures. Examining the evolution of production–living–ecological spaces (PLESs) and the spatial conflicts associated with this evolution provides an important basis for reducing land-use tensions and promoting more coordinated and sustainable spatial development. Drawing on land-use records spanning 2000–2020, this study integrates a transfer-matrix approach, a PLES conflict assessment model, and spatial autocorrelation analysis to examine the spatiotemporal evolution of PLESs and their conflict patterns in Shenmu City, China. The results show that (1) industrial production land expanded more rapidly than any other land category, mainly through the conversion of agricultural production land. Agricultural production land continued to decrease as it was converted into both industrial production land and ecological land. Grassland served as an important transitional space between production and ecological spaces, with its evolution shifting from rapid expansion in the early period to relative stability in the later period. (2) In terms of spatial conflicts, moderate conflict remained the dominant category and generally increased over time. By contrast, strong and relatively strong conflicts decreased, while weak and relatively weak conflicts gradually increased. Spatially, conflict patterns shifted from highly concentrated areas in the southeastern resource-extraction zone to a more dispersed and balanced regional distribution. (3) Global Moran’s I decreased from 0.62 to 0.49, indicating a weakening of overall spatial clustering. High–High clusters contracted into fragmented patches, whereas Low–Low clusters continued to expand in the northwestern ecological zone, reflecting the gradual improvement of local environmental conditions. Overall, although spatial conflict intensity has decreased and strong conflicts have been substantially reduced, conflicts have shifted mainly toward moderate levels rather than being fully resolved. As the dominant and still expanding category, moderate conflict represents a potential risk that requires continuous monitoring and adaptive intervention. By focusing on a county-level resource-based city, this study provides a fine-grained empirical case. It identifies an evolutionary pattern characterized by the reduction in severe spatial conflicts and the accumulation of moderate conflicts, which differs from the patterns commonly observed in urbanization-driven cities. The findings suggest that spatial conflicts in resource-based cities are highly responsive to targeted ecological governance policies. Future sustainable spatial development should be promoted through differentiated zonal governance, ecological restoration, and the green transformation of the industrial structure.