Based on theoretical mechanisms and models to demonstrate the relationship between infrastructure and common prosperity, and on the data of 208 major prefecture-level cities in China from 2010 to 2020, we empirically test the role, paths and heterogeneous effects of transportation and education infrastructure improvement on common prosperity. The study shows that transportation and education infrastructure improvements can significantly promote common prosperity, but there are regional urban heterogeneity effects and time lag effects. Transportation infrastructure improvement can establish a long term mechanism to promote common prosperity by promoting population urbanization, boosting employment, and strengthening economic agglomeration capacity, while there are obstacles to the mechanism of education infrastructure to promote common prosperity by improving population urbanization. Under the double threshold constraint of rural income share, the common prosperity effect of the two infrastructures differs. When the rural income share is in the low threshold range, the common prosperity effect of education infrastructure is significant, but the effect of transportation infrastructure fails; as the rural income share grows, the crowding-out effect of transportation infrastructure disappears; when the rural income share is in the high threshold range, the effect of education infrastructure is not significant, the marginal contribution of transportation infrastructure is positive.