With the rapid development of digital technology, the combination of technology, finance, and banking has become increasingly prominent. This article uses the information of China Bank"s fintech patent application and combines it with enterprise bank loan data to test and explore the impact of bank fintech on enterprise technological innovation and its underlying mechanism. Research has found that bank fintech has a significant promoting effect on enterprise technological innovation. After a series of endogeneity discussions and robustness tests, the basic research conclusions remain consistent. Mechanism analysis reveals that restructuring the bank credit model, optimizing the customer structure of bank credit, and alleviating the cost of bank credit and improving decision-making mechanism of bank credit are three important mechanisms for bank fintech to play a role in promoting enterprise technological innovation. In addition, bank fintech also have the function of improving the efficiency of credit resource allocation. This article provides theoretical and practical basis as well as policy inspiration for further accelerating enterprise technological innovation and deepening the financial supply side reform of banking industry development.