The deep integration of digital finance and foreign trade can drive the steady and rapid development of a high-quality economy. This article conducts an empirical analysis of the mechanisms and impact effects of digital finance on high-quality development of foreign trade (HDFT) using panel data from 30 provinces in China (excluding Tibet, Hong Kong, Macao, and Taiwan) from 2011 to 2021. The research demonstrates that digital finance significantly promotes HDFT and facilitates the achievement of sustainable development goals while enhancing financial development levels and infrastructure to advance the quality of foreign trade further. Heterogeneity test results reveal that the effectiveness of digital finance varies across regions with different financial development levels. The study also identifies threshold effects in the relationship between digital finance and HDFT, with investment environments and internet penetration rates dynamically reinforcing the sustainability of digital finance in driving HDFT.