Fintech uses advanced digital technology to change and optimize the traditional financial services business model,which is crucial to promoting the quality growth of the real economy.Taking China's A-share listed companies from 2011 to 2021 as samples,this paper adopts the fixed-effect model and considers the impact mechanism of fintech on corporate debt financing costs from the perspective of equity pledge.It is found that the development of fintech can reduce the cost of corporate debt financing.Mechanism analysis shows that fintech reduces the financing cost of corporate debt financing by reducing the equity pledge ratio of controlling shareholders.Further research also finds that fintech reduces the financing cost of corporate debt by reducing the equity pledge ratio of controlling shareholders,which is more obvious in regions with low marketization process,non-four major audit firms and non-political related companies.Therefore,the government should promote the development of fintech and promote the precise financing of real enterprises;financial institutions should prudently handle the risks of equity pledge of controlling shareholders;listed companies should enhance corporate governance and comply with the regulatory regulations to curb the undesirable phenomenon caused by the equity pledge of the controlling shareholders.