Abstract: As the core driver for optimizing agricultural production systems, agricultural new quality productive forces transform traditional farming practices through technological innovation and model upgrades, thereby playing a key role in advancing the green and low-carbon development of agriculture. Using panel data from 30 Chinese provinces (autonomous regions, municipalities, excluding Hong Kong, Macao, Taiwan and Xizang) from 2013 to 2022, this study employed a two-way fixed effects model to investigate the direct impact of agricultural new quality productive forces on agricultural carbon emission intensity. It further utilized mediating and quadratic term models to analyze the indirect effects and underlying mechanisms. The study found that agricultural new quality productive forces substantially reduced agricultural carbon emission intensity. A heterogeneity analysis showed that this carbon emission reduction effect was more pronounced in non-major grain-producing areas and regions with high agricultural technology investment. Furthermore, mechanism tests indicated two key findings: agricultural land productivity was an important mediating pathway through which agricultural new quality productive forces reduced carbon emissions, and a U-shaped non-linear relationship existed between these forces and agricultural carbon emissions. Specifically, when the index for agricultural new quality productive forces exceeded 0.58, carbon emission intensity may rebound. These conclusions provide important insights for optimizing the development strategies of agricultural new-quality productive forces and for formulating targeted, differentiated carbon emission reduction policies, thereby contributing to sustainable societal development.