In the era of the booming digital economy and global industrial landscape reshaping, the digital transformation of supply chains has surpassed the scope of technological upgrading and become an important strategy for enterprises to reconstruct their competitive advantages and deeply integrate into the global market. Through the real-time perception network woven by the Internet of Things, the intelligent decision engine driven by artificial intelligence, and the deep integration with the trustworthy traceability system built by blockchain technology, enterprises are promoted to transform from a single manufacturing node to a collaborative ecological center that extends upstream and downstream. This transformation not only enhances the closeness of industrial connections and the radiation range of ripple effects, but also fundamentally improves the comprehensive competitiveness of enterprises in the international market, providing deep momentum for the sustained growth of the scale of enterprise export trade. To further explore the intrinsic relationship between supply chain digitization and enterprise export trade, this paper selects data from A-share listed companies from 2012 to 2022 as the basis and uses a DID model to identify and test the causal relationship between the two. The results reveal that supply chain digitization significantly increases the scale of enterprise export trade. After a series of robustness tests, the main conclusion still holds significant validity. Mechanism testing shows that supply chain digitization mainly increases the scale of enterprise export trade through two key channels: improving supply chain efficiency and intermediate input quality. Heterogeneity analysis indicates that supply chain digitization has a stronger driving effect on the scale of export trade of enterprises with higher growth, higher management efficiency, industry technology intensity, and lower supplier concentration. This paper reveals the role and heterogeneous characteristics of supply chain digitization in enhancing the scale of export trade, which not only provides a theoretical basis for enterprises to formulate strategies to expand their scale of export trade, but also provides valuable reference and inspiration for China to win strategic initiative in global economic competition and achieve the grand goals of “digital power” and “trade power”.