Abstract: Counties are important geographical units for China's economic and social development. Agricultural technological progress is one of focuses for reducing China's urban-rural income gap and promoting common prosperity. Based on the county level data in Henan Province from 2010 to 2019 and the theory of technology diffusion, this study evaluated the agricultural total factor productivity by the DEA-Malmquist index, analyzed the impacts of the progress on urban-rural income gap by the dynamic spatial Durbin model and partial differential decomposition method, and discussed the degree, sphere, and path of the effects. Results show that the progress of agricultural frontier technology mainly contributes to the progress of agricultural technology in Henan Province and the process accompanies by the losses of agricultural technical efficiency as well. A significant spatial agglomeration of urban-rural income gap exists in Henan Province. Agricultural technological progress is negatively correlated with the income gaps that decreases the gaps by 0.013. From the time dimension, the technology spillover effect coefficient is significantly negative in short-term, but not significant in the long-term. About the regional heterogeneity and regional agricultural technological progress with different per capita GDP levels have different inhibitory effects on the income gaps. For geographical distances, the concentrated area of spatial spillover effects is within 150 km, and the effects become smaller and smaller with the increase of distance. The study proves that agricultural frontier technological progress is an effective way to suppress the spillover path of urban-rural income gap. Therefore, to narrow the income gaps among counties, this study suggests continuing to increase investment in agricultural science and technology and promote their results' transformation from theory to practice, reducing the transaction cost of technology diffusion, breaking the barriers to agricultural technology spillover in counties, and setting a county-level technology information exchange network.