Abstract: Properly devised environmental regulations serve as a crucial guarantee for promoting the green transformation of agriculture. Based on the provincial panel data from 2005 to 2022, this paper empirically tests the impact of environmental regulation on agricultural green transformation from the perspective of green total factor productivity (TFP), and focuses on the heterogeneity of this impact and the underlying mechanism. The findings show that: 1) environmental regulation had a significant positive “U”-shaped impact on agricultural green transformation, and the intensity of environmental regulations in the vast majority of provinces has not surpassed the “U” inflection point that promotes agricultural green transformation. 2) Environmental regulation primarily enhances overall green TFP growth through improvements in green technical efficiency, and green technical efficiency can surpass the “U” inflection point earlier than green TFP. 3) The mechanism test indicates that environmental regulation mainly derived agricultural green transformation through the linear mechanism of stimulating agricultural green technological innovation and the nonlinear mechanism of improving the misallocation of land and labor factors. 4) The heterogeneity analysis shows that environmental regulation had a significant positive “U”-shaped impact on agricultural green transformation only in central and western regions, while the impact is insignificant in eastern regions. For provinces with medium and high levels of agricultural green development, environmental regulation had a significant positive “U”-shaped impact on their agricultural green transformation, whereas the impact is insignificant for provinces with low levels of agricultural green development. The conclusion of this article provides policy support for the government to reasonably design the intensity of agricultural environmental regulation, promoting a win-win situation for both agricultural development and environmental protection.