Green financial development can improve the business conditions for enterprises, thus alleviating the level of financing constraints for SMEs. This study uses the double fixed effect model to conduct an empirical analysis on China's listed SMEs from 2009 to 2020 in order to explore the relationship between the green finance development and the financing constraint level of SMEs. It turns out that SMEs generally face financing difficulties, while green finance development effectively alleviates their financing constraints by improving their profitability, operating capacity and expanding their scale, but the rapid economic growth and the continued expansion of the financial industry will take a roll on its easing effect for SMEs' financing constraints. Further analysis shows that the more perfect the development of green finance is, the more significant its effect on easing the financing constraints of SMEs will be. Furthermore the difference between the nature of enterprises' property right and of industries varies its alleviating effect. All in all, such measures are expected to carry out to strengthen the potentials of green financial development on the financing constraints faced by SMEs in ways of implementing the green development concept and green financial policies, and optimizing the financial industry structure, etc., and giving full play to the role of green finance in solving the financing problems of SEMs to promote their green transformation.