Green finance offers essential financial services to promote green economic development, focusing on mitigating climate change, protecting the environment, and advancing clean energy initiatives. This study examines the relationships among green finance development, environmental attention, and investment in clean energy (hydroelectric power) via panel data from Chinese prefecture-level cities from 2010 to 2021. The empirical results indicate that green finance significantly increases investment in hydroelectricity. Additionally, government environmental attention and public environmental concern positively moderate this relationship. The heterogeneity analysis indicates regional and scale differences in the impact of green finance on hydroelectric power investment. In particular, a more significant effect on hydroelectric power investment is observed in the western and central regions, and small-scale cities experience a similar influence that megacities do.