Integrating digital technology into supply chain development strengthens supply chain digitization, improving technical communication and transparency at various nodes. This study examines the effect of supply chain digitization on the carbon emissions of listed companies and their transmission mechanisms, leveraging the quasi-natural experiment of China's 2018 Supply Chain Innovation and Application pilot policy. The findings reveal that implementing supply chain digitization led to a 5.4% reduction in carbon emissions in pilot companies compared with nonpilot counterparts, according to 2012–2022 data on 2,828 listed companies. Mechanism analysis indicates that supply chain digitization achieves emission reductions mainly by facilitating green technological innovation and alleviating information asymmetry. Heterogeneity analysis reveals more potent effects in central regions, resource-rich areas, firms with concentrated supply chains, long inventory turnover, and high-tech or heavily polluting industries. This study offers valuable insights for optimizing policies to strengthen supply chain digitization and assist companies in reducing their carbon emissions.