Abstract In the context of accelerated industrialization and urbanization, the importance of the green energy sector has become increasingly prominent. From the perspective of the role of the financial system, this article deeply explores the role mechanism and environmental constraint relationship of financial instruments in green energy development. The article constructs a measurement model of financial instruments on the efficiency of green energy development, introduces data spatial correlation into the econometric analysis framework, and establishes a spatial econometric model to analyze the impact of financial instruments on development efficiency. By testing the data from 2008 to 2020, the study shows that the level of global financial means support passes the significance level, and the magnitude of the mediating effect when the spatial Durbin model is simplified to an error model is about 13.5%. The study also found that enhancing green energy development can positively affect neighboring regions. This paper provides an effective methodological path for studying the role of financial instruments in green energy development, which is of great theoretical and practical significance for promoting the development of the green energy sector.