Taking A share listed companies from 2001 to 2016 as the research sample, we used the difference in difference model to investigate the impact of interest rate marketization on maturity mismatch between investment and financing. It is found that interest rate marketization restrains maturity mismatch between investment and financing in enterprises, while financing constraint plays an intermediary role in the process. Specifically, scrapping the top limitation of loan rate increases the availability of long term loans, while lending rate floor relaxation reduces the debt financing cost of enterprises. In addition, it is also found that the constraint of interest rate marketization on the maturity mismatch between investment and financing is more significant in small scale and high growth enterprises. The paper enriches the literature on the economic consequences of interest rate marketization and the influencing factors of the maturity mismatch between investment and financing. The research conclusion has some enlightenment significance for promoting the deepening reform of China’s financial system.