<p>With the widespread adoption of digital technologies across various industries, digital transformation has provided significant benefits to enterprises, including enhanced data sharing, process optimization, and efficiency improvement. Based on the data of A-share listed enterprises in China from 2019 to 2022, this paper explores the impact of digital transformation on supply chain efficiency and its underlying mechanism. The findings reveal that digitalization of enterprises significantly enhances their supply chain efficiency. To be more specific, the transmission mechanism indicates that the digitalization improves the efficiency of supply chain by increasing external transaction costs and enhancing management capabilities, and customer concentration plays a negative moderating role during this process. Moreover, heterogeneity analysis demonstrates that the impact of digitalization on supply chain efficiency is more significant in supply-chain-sensitive industries and large enterprises. This paper not only enriches the research on digital transformation and supply chain efficiency but also provides empirical evidence for enterprises to promote digital transformation, improve supply chain efficiency and achieve sustainable development.</p>