Abstract: Environmental regulation serves as a critical pathway for China to achieve its “dual carbon” goals and promote the green transformation of agriculture. Based on panel data from 30 provinces in China from 2011 to 2022, excluding Xizang, Hong Kong, Macao, and Taiwan, this study employs panel regression models and fuzzy-set qualitative comparative analysis to examine the effects of environmental regulation on agricultural carbon intensity and the underlying mechanisms. The results show that environmental regulation significantly reduces agricultural carbon intensity, and this conclusion remains robust after multiple robustness tests. Regional heterogeneity analysis indicates that the inhibitory effect of environmental regulation is significantly stronger in the eastern and central regions than in the western region, while the carbon reduction effects of different types of environmental regulation vary markedly across regions. Mechanism analysis further reveals that environmental regulation can reduce agricultural carbon intensity by promoting green technological innovation. Moreover, fiscal support for agriculture positively moderates the effects of comprehensive environmental regulation, command-and-control regulation, and voluntary participation regulation on agricultural carbon intensity, but does not exhibit a significant moderating effect on market-incentive environmental regulation. From a configurational perspective, no single factor constitutes a necessary condition for achieving low agricultural carbon intensity. Instead, three main configuration paths are identified, namely the command-dominated type, the multi-party collaborative type, and the dual-driven type.