This paper explores the extent to which financial flexibility affects the financialization of enterprises based on the financial data of A-share listed companies in Shanghai and Shenzhen from 2011 to 2020, followed by an introduction of financing constraints for an empirical test of whether they play a moderating role in the relationship between the two. The study finds that financial flexibility significantly promotes the financialization of enterprises, and the promotion effect varies significantly across industries with different competition, property rights and enterprise size in different regions. In competitive industries, financial flexibility is more likely to enhance the financialization level of enterprises; in the economically developed eastern region, the promotion effect is particularly remarkable in state-owned enterprises and large-scale enterprises; financing constraints positively regulate the relationship between the two. A breakdown of financial flexibility reveals that in highly competitive industries, financial constraints have a more significant moderating effect on debt flexibility and corporate financialization; the facilitating effect of cash flexibility is not significant among SOEs in the central and western regions, while the facilitating effect of debt flexibility on SOEs is significantly higher than that of non-SOEs in both the eastern and central and western regions. Accordingly, enterprises should raise their awareness of financial flexibility and reasonably choose financial flexibility policies. At the same time, government departments should increase assistance to non-SOEs by broadening their financing channels and easing their financing pressure.