Using provincial panel data from China spanning 2011 to 2022, this paper analyzes the impact, mechanisms, and regional differences in digital trade’s effects on regional green innovation. It also explores the threshold effect between digital trade and green innovation, with environmental regulation serving as the threshold variable. The results indicate the following: first, after accounting for government intervention, foreign direct investment, human capital, industrialization, information technology infrastructure, and economic development, digital trade significantly promotes regional green innovation. This conclusion remains valid after a series of robustness tests. Second, digital trade promotes regional green innovation through three mechanisms: accelerating industrial structure upgrading, promoting industrial agglomeration, and enhancing technology transfer. Third, environmental regulation leads to a non-linear relationship between digital trade and green innovation. Higher levels of environmental regulation make digital trade’s contribution to green innovation more significant. Finally, the effects of digital trade on green innovation vary by region in China. This impact is more pronounced in eastern provinces, regions with advanced digital economies, areas with well-developed transport infrastructure, and provinces with a higher degree of trade openness. These findings hold substantial implications for advancing green innovation and promoting sustainable social development in China.