With the increasing awareness of sustainable development, ESG performance has gradually become a focus of attention for enterprises and their stakeholders. Taking Chinese Ashare listed companies as a sample, this article examines the impact of improving customer ESG performance in supply chain partnerships on supplier green innovation decisions. Research has found that improving customer ESG performance can significantly enhance suppliers level of green innovation, indicating a supply chain contagion effect in customer ESG performance. The mechanism analysis found that the improvement of customer ESG performance mainly affects supplier green innovation through resources acquisition and stakeholder pathways channels. Further research has found that when customers are non polluting enterprises, suppliers are nonstateowned enterprises, and customers place greater emphasis on fulfilling their social responsibilities, the improvement of customer ESG performance has a more significant impact on supplier green innovation. This article enriches the research on green innovation in supplier enterprises from the perspective of external collaborators, and provides an important basis for supply chain enterprises to achieve green transformation through the contagion effect of ESG information disclosure.