Abstract: Exploring the driving effects and transmission mechanisms of digital economy-agriculture integration on the modernization of agricultural industrial chains and supply chains holds significant practical implications for advancing agricultural and rural modernization. Based on panel data from 31 Chinese provinces spanning 2011 to 2023, this paper constructs measurement systems for digital economy-agriculture integration and the modernization of agricultural industrial chains and supply chains, and employs two-way fixed effects models and mechanism analysis models to empirically examine their direct impacts and transmission pathways. The results show that digital economy-agriculture integration significantly promotes the modernization of agricultural industrial chains and supply chains, and this conclusion remains robust after a series of robustness checks, including alternative estimation methods, sample exclusion, winsorization, replacement of the core explanatory variable, system GMM estimation, and instrumental variable approaches. Mechanism analysis indicates that the enhancement of agricultural total factor productivity and the integrated development of rural primary, secondary, and tertiary industries constitute the two primary pathways through which digital economy-agriculture integration indirectly drives the modernization upgrading of agricultural industrial chains and supply chains. Furthermore, heterogeneity analysis reveals that the promoting effect of digital economy-agriculture integration exhibits a gradient pattern with the central region leading, followed by the eastern region, and the western region relatively weaker, with more pronounced impacts in major grain-producing areas and regions with higher levels of digital economic development. Accordingly, differentiated promotion strategies should be implemented based on the regional gradient pattern, targeted policies should be devised along the key transmission pathways, and differentiated factor guarantee and effect tracking mechanisms should be established.