The financing difficulties of small and medium-sized enterprises have become a hot issue that enterprises,governments and academia generally pay attention to.Supply chain finance,as an emerging tool combining industry and finance,can solve the financing difficulties of SMEs.This paper takes the enterprises listed on GEM of Shenzhen Stock Exchange from 2012 to 2020 as the research object and empirically analyzes the mechanism of supply chain finance on financing constraints of SMEs.The results show that supply chain finance can significantly alleviate the financing constraints of SMEs.Further research shows that supply chain finance can reduce the cost of equity financing and debt financing of enterprises,so as to promote the optimization of their own capital structure and attract more investment and financing.Equity structure has a significant moderating effect on supply chain finance to ease SMEs'financing constraints.High equity concentration can positively strengthen the easing effect of supply chain finance on SMEs'financing constraints.This paper enriches the relevant research in the field of supply chain finance and provides more comprehensive theoretical support and empirical evidence for supply chain finance to ease the financing constraints of SMEs.