Against the backdrop of the intertwined challenges of global climate change and geopolitical risks, the vulnerability of food security has become increasingly prominent, and enhancing grain production resilience has emerged as a critical task for safeguarding national food security. As a key foundation for agricultural digital transformation, digital infrastructure provides essential support for improving grain production resilience. Based on panel data from 287 prefecture-level cities in China from 2010 to 2023, this study employs the implementation of the “Broadband China” strategy as a quasi-natural experiment and constructs a multi-period difference-in-differences model to investigate the impact of digital infrastructure development on grain production resilience and its underlying mechanisms. The results show that digital infrastructure construction significantly enhances grain production resilience, and the findings remain robust after addressing potential endogeneity concerns and conducting a series of robustness checks. Mechanism analysis reveals that technological innovation, human capital, and agricultural insurance compensation are important transmission channels through which digital infrastructure improves grain production resilience. Specifically, technological innovation promotes the diffusion of agricultural technologies through enhanced computing capacity and information sharing, thereby improving resource allocation efficiency; human capital facilitates labor skill upgrading through both incentive and adaptive mechanisms; and agricultural insurance compensation alleviates information asymmetry through digital technologies, improves claims settlement efficiency, and strengthens financial buffers against post-disaster shocks. Heterogeneity analysis reveals that the positive effect of digital infrastructure construction on grain production resilience is more pronounced in coastal regions, higher-ranked cities, areas with relatively flat terrain, and the period after 2015. Therefore, efforts should be made to accelerate the coordinated development of digital infrastructure with agricultural technological innovation, human capital cultivation, and risk protection systems, optimize the spatial allocation of digital resources, and enhance the precision of digital technology-enabled agricultural production, thereby providing policy support for strengthening grain production resilience and safeguarding national food security.