Abstract: In the context of innovation-driven and low-carbon strategies, assessing the role of agricultural green technology innovation in reducing carbon emissions under environmental regulation is essential for strengthening green technological capability, refining policy design, and advancing sustainable agricultural development. Using panel data from 31 Chinese provinces (autonomous regions and municipalities, excluding Hong Kong, Macao, and Taiwan) for the period 2001 to 2022, this study applies a panel threshold regression model to investigate how agricultural green technology innovation influences carbon emission reduction, with particular attention to the moderating role of different types of agricultural environmental regulation. The findings suggest that: (1) The improvement of agricultural green technology innovation helps reduce agricultural carbon emissions, in particular, pollution prevention oriented innovations playing a greater role than resource conservation innovations in agricultural emission reduction. It indicates that the structural characteristics of technological innovation exert a significant impact on the agricultural emission reduction pathways. (2) Agricultural environmental regulation significantly reduces agricultural carbon emissions, though with a policy lag, and resource conservation oriented regulation exerts a stronger direct effect on emission reduction. (3) Agricultural environmental regulation and its subtypes (resource conservation and pollution prevention) all exhibit single-threshold effects, in particular, resource conservation oriented regulation and pollution prevention oriented regulation can more effectively activate the potency corresponding agricultural green technology innovations in agricultural carbon emission reduction by means of lower thresholds and greater efficiency. This implies that strengthening environmental regulation can further stimulate agricultural green technology innovation and reduce carbon emissions, while precise alignment between differentiated regulations and green innovations can better enhance emission-reduction effects, thereby confirming that the Porter Hypothesis remains valid in the agricultural sector. Moreover, the single-threshold effect also indicates that China’s current agricultural environmental regulations remain within a moderate range, effectively promoting green agricultural technology innovation and advancing agricultural green development. Based on these findings, policymakers should actively promote agricultural green technology innovation, especially in the development, dissemination, and adoption of pollution prevention technologies. At the same time, more emphasis should be placed on strenghthening resource conservation oriented environmental regulations, and improving the legal and regulatory framework for agricultural environmental protection, in order to accelerate the transition toward low-carbon and sustainable agriculture.