Abstract: Driven by the dual carbon goals and the Digital China strategy, green computing infrastructure construction has become an important foundation for promoting the coordinated development of digitalization and green transformation. However, systematic causal evidence on its effects in the agricultural sector remains limited. Using the national green data center pilot program as a quasi natural experiment, this study examines the impact of green computing infrastructure construction on the synergistic development of agricultural digitalization and green transformation and its underlying mechanisms. The analysis is based on 3,237 city year observations for 249 prefecture level cities in China from 2011 to 2023 and employs a staggered difference in differences model. The results show that green computing infrastructure construction significantly improves the coupling coordination degree of agricultural digitalization and green transformation, with an estimated coefficient of 0.076 after controlling for relevant variables, which is significant at the 1% level. The results remain robust after parallel trend tests, corrections for sample selection bias, treatments of endogeneity, and a series of other robustness checks. Mechanism analysis indicates that green computing infrastructure construction mainly promotes the synergistic development of agricultural digitalization and green transformation by facilitating the circulation of data factors, expanding the application of clean energy, and promoting the integration of green computing technologies with agricultural technologies. Heterogeneity analysis shows that the policy effect is significantly stronger in the western region than in the northeastern region, while the differences among the eastern, central, and northeastern regions are not significant. All pilot batches exhibit significant positive effects, but the policy effect does not increase monotonically across batches. No significant differences are observed among regions with different intensities of environmental fiscal expenditure. The policy effect is significantly stronger in regions with medium levels of digital inclusive finance than in those with low levels, whereas the difference between regions with high and low levels is not significant. These findings provide empirical evidence for optimizing the spatial layout of green computing infrastructure and promoting the integrated development of agricultural digitalization and green transformation.