In order to promote the sustainable development of society, the state proposes to build a green financial system to guide social capital to provide financial support for green projects. As an important direct financing tool in the green financial system, the development of green bonds has played an important role in promoting the reform of ecological civilization system. In this context, exploring the factors affecting the coupon interest rate of green bonds will help to reduce the financing costs of relevant subjects. Using empirical analysis methods, the possible factors affecting the green bond coupon rate are selected from the macro, corporate and bond elements. Through the establishment of multiple regression models, market interest rates, domestic inflation, corporate registered capital, return on net assets and credit are finally obtained. The rating has a significant impact on the green bond coupon rate and provides reasonable advice for the continued development of the green bond market.