The contagion effect is a significant driver of corporate financialization. By utilizing the data from Shanghai and Shenzhen A-share listed companies from 2007 to 2020 to analyze the peer behaviors within interlocking directorate networks, this paper examines the contagion effect of corporate financialization and its economic consequences. The findings reveal that the peer behaviors in interlocking directorate networks lead to a pronounced contagion effect in corporate financialization, influenced by factors such as network position, managerial characteristics, and governance environment. Further research indicates that the peer behaviors concerning financialization decisions within these networks exacerbates the transmission of financial risks among firms, reduces their capacity to bear risk, diminishes investments in research and development, and lowers investment efficiency. Consequently, corporate financialization should attach importance to learning and imitation among firms through interlocking directorate networks, and prevent the risk of a turn from substantive to speculative activities spreading through these networks.