Abstract: Although existing studies suggest that digital infrastructure construction positively enables environmental performance, its relationship with corporate environmental investment decisions remains unclear. The paper employs a multi-period Difference-in-Differences (DID) model to empirically investigate the impact of digital infrastructure construction on corporate environmental protection investment. The study finds that digital infrastructure construction significantly reduces the level of corporate environmental investment. Further structural analysis reveals that this cost-reducting effect stems from the optimization of the investment structure, specifically where enterprises substitute costly end-of-pipe treatment investments with increased front-end preventive investments. The decline in environmental investment does not weaken corporate environmental compliance, but instead reduces pollution discharge fees and does not trigger more stringent environmental penalties. Digital infrastructure construction reduces firms’ reliance on traditional environmental investments by improving resource allocation efficiency, promoting green technology innovation, and enhancing regional green total-factor energy efficiency. Heterogeneity analysis shows that the aforementioned effects are more pronounced in enterprises with lower levels of digital transformation, higher financing constraints, greater technological intensity, larger scale, or more stringent environmental regulations. In conclusion, this paper offers important policy insights for optimizing digital infrastructure investment layouts and building a technology-embedded environmental governance system.

Key words: digital infrastructure construction, “broadband China”, corporate environmental investment, front-prevention, end-treatment