Abstract: Agricultural green innovation is a core engine driving the green transformation of agriculture. How to leverage digital infrastructure to empower the diffusion of green knowledge and the supply of green technologies is of great significance. Based on a panel data of 300 prefecture-level administrative regions from 2005 to 2023, this paper constructs a quasi-natural experiment by taking advantage of the “Broadband China” strategy and uses a multi-period difference-in-differences (DID) model to explore the impacts of digital infrastructure construction on agricultural green innovation and its mechanism. Research results show that digital infrastructure construction can effectively promote agricultural green innovation, and this effect is mainly achieved by promoting the aggregation of innovation and R&D talents and the development of digital finance. Moreover, this effect shows significant heterogeneity across regions and between grain functional areas. Further analysis reveals that digital infrastructure construction has a significant promoting effect on agricultural green innovation in both central and western regions, especially in the central grain production areas. Meanwhile, the promoting effect of digital infrastructure construction on agricultural green innovation in grain production areas is significant in both central and western regions, while its impact on non-grain production areas is more prominent in the western region. Based on these findings, it is recommended to continuously strengthen the construction of digital infrastructure, focus on promoting the aggregation of innovation and R&D talents and the development of digital finance, and further leverage its promoting effect on agricultural green innovation through differentiated empowerment of digital infrastructure.