In the current critical period of China’s comprehensive advancement of rural revitalization and common prosperity strategies, the development of new quality productive forces in agriculture has emerged as the core endogenous driver for promoting urban-rural common prosperity. Given that agricultural technological innovation serves as the concrete manifestation of new quality productive forces in the agricultural sector, this study empirically examined both the overall impact of agricultural technological innovation on urban-rural common prosperity and its multidimensional nonlinear effects using panel regression models, mediation effect models, and nonlinear regression models, based on 1820 county-level samples spanning 2000-2020. The findings revealed that agricultural technological innovation significantly enhances urban-rural common prosperity, a conclusion that remains robust after addressing endogeneity concerns and conducting multiple robustness tests. Mechanism analysis demonstrated that agricultural technological innovation primarily drives common prosperity through enhancing agricultural labor productivity and improving agricultural technological conditions. Heterogeneity analysis indicated more pronounced effects in central regions, counties with more advanced digital rural development, higher economic development levels, and abundant water resources. Further investigation identified an inverted N-shaped nonlinear relationship between agricultural technological innovation and the “commonality” dimension, while an inverted U-shaped nonlinear relationship emerges with the “affluence” dimension. This research will provide crucial theoretical references and empirical evidence for understanding how agricultural technological innovation facilitates phased improvements in urban-rural income growth and distribution amidst the new wave of technological revolution.