[Objective] The impact of supporting policies on land-use efficiency for resource-based cities in the Yellow River basin was explored, in order to provide theoretical reference for the efficient use of land and the implementation of supporting policies for resource-based cities in the Yellow River basin. [Methods] The urban land-use efficiency of resource-based cities in the Yellow River basin from 2008 to 2021 was measured using the undesired output super-efficient SBM model. The difference-in-differences and mediation effect models were employed to examine the impact of supporting policies on urban land-use efficiency, as well as their heterogeneity and channels of impact. [Results] ① During the study period, the overall urban land-use efficiency in the Yellow River basin exhibited an increasing fluctuation trend. In addition, the difference in land-use efficiency between resource-based cities and non-resource-based cities expanded after the implementation of the supporting policy. ② Supporting policies promoted the land-use efficiency of resource-based cities in the Yellow River basin, but the impact had a time-lag effect. ③ The impact of supporting policies had significant heterogeneity in different types of resource-based cities in different spatial locations. Supporting policies had a promotional effect on cities upstream of the basin but had an insignificant impact on cities midstream and downstream of the basin. The impact on mature cities and recessionary cities was more significant than that on growing and regenerating cities. ④ Furthermore, supporting policies could optimize land-use efficiency through industrial structure adjustment and environmental governance. [Conclusion] Policy tools must be used to guide urban development, adopt measures according to local conditions, and focus on industrial structure adjustment and environmental governance to improve the quality and efficiency of land use and embed land functions into the high-quality development of cities in the Yellow River basin to exert its advantages.