Under the background of the growing popularity of the concept of green development, improving the green utilization efficiency of urban land has become an important strategy for promoting sustainable urban development. As a key initiative of the government to promote green development and ecological civilization construction, green fiscal expenditure has attracted much attention in terms of its input and actual effect. However, despite the growing importance of green fiscal expenditure, the research on how it affects the green utilization efficiency of urban land and the mechanism behind its impact remains limited. In this paper, 259 cities in China from 2010 to 2021 are selected as the research sample, and the non-expected super-efficiency (Super-SBM) model is used to evaluate the green utilization efficiency of urban land, and then the fixed-effect panel model is used to analyze the direct effect of green fiscal expenditure on the green utilization efficiency of urban land. On this basis, the intrinsic effect mechanism is further investigated. The results show that: (1) Green fiscal expenditure significantly improves the green utilization efficiency of urban land. (2) Green fiscal expenditure can improve the green utilization efficiency of urban land by promoting green technological innovation and improving public environmental concerns. (3) Fiscal pressure inhibits the improvement effect of green fiscal expenditure on the green utilization efficiency of urban land, while environmental regulation and urban entrepreneurial activities promote this effect. (4) The improvement effect of green fiscal expenditure is significant in the eastern and central regions and non-resource cities, but not in the western region and resource cities. Compared with previous studies, this paper makes two main contributions: First, it explores the mechanisms through which green fiscal expenditure enhances the green utilization efficiency of urban land by promoting green technological innovation and increasing public environmental awareness, and analyzes the moderating effects of fiscal pressure, urban entrepreneurial activity, and environmental regulation on this process. Second, it reveals the locational and resource-based heterogeneity of the impact of green fiscal expenditure on the green utilization efficiency of urban land, providing empirical evidence and a basis for the differentiated formulation of urban green fiscal policy and the enhancement of urban land green utilization efficiency. This research contributes to the literature on the impact of green fiscal policy by offering new insights and perspectives on the underlying drivers and practical pathways for enhancing the green utilization efficiency of urban land. It provides a research foundation and decision-making reference for promoting efficient and sustainable land use. It is essential to emphasize the driving roles of green technological innovation and public environmental awareness, deepen fiscal system reform, strengthen environmental regulation, encourage and enhance urban entrepreneurial activity, and implement targeted policies to promote the efficient and sustainable use of land resources.