Taking return on assets (ROA) as an indicator to measure the profitability of Banks, the external data of eight relevant commercial Banks in China from 2015 to 2019 were selected. Fintech index was used to analyze and study the influence degree and form of Fintech on the profitability of various types of commercial Banks. The analysis concluded that the profitability of banks declined during the initial stage of Fintech. However, with the gradual development and progress of Fintech, the full use of Fintech by various commercial Banks can gradually improve their profitability. The development of Fintech is positively correlated with the profitability of commercial banks.