Digital infrastructure is an important engine to drive the low-carbon transformation of enterprises, foster new quality productivity, and enhance new growth drivers. This paper takes 2,749 Chinese A-share listed companies from 2006 to 2021 as samples to investigate the impact of digital infrastructure on corporate carbon emissions, its mechanism and heterogeneity through time-varying DID. The findings of this paper are as follows. Digital infrastructure can significantly reduce the level of corporate carbon emissions after a series of robustness tests such as placebo tests and PSM-DID. The impact mechanism test shows that digital infrastructure mainly promotes corporate carbon emission reduction through the “technology dividend” effect and the “structural dividend” effect, that is, reducing corporate carbon emissions through green technology innovation, energy efficiency improvement, and digital transformation. Heterogeneity analysis shows that for state-owned enterprises, enterprises with fierce industry competition, enterprises in non-resource-based cities and non-old industrial bases, digital infrastructure plays a stronger role in promoting corporate carbon emission reduction. This study provides empirical evidence and policy implications for how to use digital infrastructure to empower enterprises to reduce carbon emissions.