This paper takes the financial data from A?share manufacturing companies listed in Shanghai and Shenzhen from 2012 to 2022 as the research sample， and applies the two?way fixed effect model to empirically test the impact of financialization of manufacturing companies on their profitability. The results show that the financialization has a significant inhibitory effect on their profit rate； that the mechanism test reveals that monetary policy plays a regulating role between the two， and financialization inhibits the growth of profit rate by crowding out real investment and intensifying financing constraints； and that the financialization of large enterprises， non?state?owned enterprises， and enterprises with long?term financial assets has a more significant dampening effect on profitability. Therefore， the regulatory authorities should strengthen their supervision on financial investment of manufacturing enterprises， intensify the supply?side structural reform， and put the focus of economic development on the entity enterprises， so as to enhance their profitability to promote manufacturing enterprises’ virtuous circle of financial activities and production and operation.