With the growing emphasis on sustainable development, the impact of customer environmental performance on innovation activities has attracted more attention. Using a dataset of Chinese A-share listed companies from 2009 to 2022, this study empirically investigates the relationship between customer environmental performance and supplier green innovation. The results show that customer environmental performance has a significant positive effect on supplier green innovation. Mechanism analysis reveals that customer environmental performance promotes supplier green innovation through four pathways: supply chain transmission, market investment expectations, institutional policies, and financial constraints. The impact of customer environmental performance on supplier green innovation is more pronounced when the customer enterprise is state-owned, the supplier enterprise is state-owned, or the supplier enterprise holds ISO14001 certification. This study contributes to the literature on supply chain sustainability and provides valuable insights for enterprises on enhancing competitiveness and promoting sustainable supply chain transformation through improved environmental performance.