The booming digital economy has a profound impact on corporate organizations. Starting from the perspective of supply chain management, this paper adopts the empirical data of China's A-share listed companies in Shanghai and Shenzhen from 2008 to 2020 to empirically test the impact of enterprises' digital transformation on their customer concentration and its channel mechanism. The study finds that digital transformation can significantly reduce customer concentration. This finding has udergone a series of endogeneity tests and robustness tests. Mechanism tests find that digital transformation reduces firms dependence on key customers by enhancing netizens' attention and innovation ability. Further heterogeneity analysis shows that the weakening effect of digital transformation on firms' customer concentration is more prominent among non-state-owned firms and firms with low financing constraints. This study not only reveals the mechanism of the impact of digital economy development on enterprise customer concentration and enriches the related research on enterprise digitalization and supply chain management, but also provides important insights into how supply chain enterprises can reduce their overdependence on major customers with the help of digital transformation.