Abstract: This study examines the impact of transportation infrastructure on urban–rural income from three dimensions: comprehensive transportation infrastructure, highway infrastructure, and railway infrastructure. A variety of analytical methods are employed, including ordinary least squares （OLS）, boundary tests, the Heckman two-stage model, propensity score matching （PSM）, and the instrumental variable two-stage least squares （IV-2SLS） approach, providing new evidence for determining the direction of the effect. By introducing agricultural terms of trade and agricultural mechanization as mediating variables, a mediation effect model is applied to elucidate the specific mechanisms through which transportation infrastructure mitigates urban–rural income disparities, thereby offering a novel contribution to the study of underlying mechanisms.The findings reveal that transportation infrastructure exerts a significant positive effect on narrowing the urban–rural income gap. This conclusion remains robust even after multiple robustness checks and the treatment of endogeneity. Heterogeneity tests show that transportation infrastructure consistently contributes to reducing income disparities between urban and rural areas across various regions. Mechanism analysis shows that agricultural trade conditions and agricultural mechanization serve as mediators linking transportation infrastructure to changes in the income disparity between urban and rural areas. This study offers new evidence for evaluating how transportation infrastructure influences income disparities between urban and rural areas, while also enhancing the understanding of the underlying mechanisms.