The coupled development of economic and ecological systems is crucial for achieving sustainable growth, with the financial system playing a pivotal adaptive role. Green financial innovation (GFI) is central to enhancing this adaptation. Urban land use eco-efficiency (ULUEE) serves as an effective measure of economic–ecological coupling. Using China’s Green Finance Reform and Innovation Pilot Zones (GFRPZs) as a quasi-natural experiment, this study assesses the impact of GFI on ULUEE, employing panel data from 283 prefecture-level cities (2013–2021). The results show that GFI significantly enhances ULUEE through technological spillovers, strengthened environmental regulation, industrial upgrading, and resource agglomeration. Heterogeneity analyses further reveal that GFI’s positive effects are more pronounced in economically developed regions, cities without legacy heavy-industry reliance, and those with deeper financial development. Additionally, GFI demonstrates cross-regional spillover effects, effectively interacting with other environmental policies. While GFI’s impact is more pronounced in economic growth, its ecological governance improvements are modest. This study provides critical insights for tailored green financial policies aimed at harmonizing economic and ecological objectives.