Agricultural new quality productivity, as a crucial component of new quality productivity, offer fresh insights and innovative pathways for advancing common prosperity among farmers and in rural areas. Hence, this paper empirically examines the impact mechanism of agricultural new quality productivity on common prosperity among farmers and in rural areas, based on panel data from 30 provinces and municipalities in China spanning from 2012 to 2022. The results show that the impact of agricultural new quality productivity on common prosperity among farmers and in rural areas has a U-shaped nonlinear characteristic with increasing marginal returns. When the development level of the former is higher than 0.508, it is conducive to promoting common prosperity among farmers and in rural areas. The heterogeneity analysis shows that as the characteristic variable with the greatest impact on the level of common prosperity among farmers and in rural areas, in regions with lower levels of residents' consumption, the marginal impact of agricultural new quality productivity on common prosperity among farmers and in rural areas is larger and the inflection point shifts to the left. The mechanism analysis reveals the key role of farmers' entrepreneurship and the phased characteristics formed by the asynchronous changes in farmers' income and the income gap. In addition, the higher the level of agricultural socialized services, the more significant the U-shaped effect of agricultural new quality productivity; while excessive rural income disparity will cause this impact to degenerate into a linear negative effect. Therefore, the government needs to consolidate the elements and institutional basis of agricultural new quality productivity, stimulate farmers' enthusiasm for entrepreneurship, correctly handle the relationship between "common" and "prosperity", and vigorously develop agricultural socialized services to jointly build a solid foundation of agricultural new quality productivity for common prosperity among farmers and in rural areas.