Based on data from Chinese listed firms between 2008 and 2022, this paper investigates the relationship between customer environmental information disclosure and suppliers’ green innovation. We find that customer environmental information disclosure quality significantly enhances suppliers’ green innovations, indicating a backward spillover effect of environmental practices in the vertical supply chain relationship. The moderating effect analysis further demonstrates that this effect is more pronounced when customers exert higher bargaining power or suppliers have improved access to supply chain financing, but weaker when customer instability is present. Further analysis shows that compared with the quantity of suppliers’ green innovations, customer environmental information disclosure has a more significant promoting effect on the quality of suppliers’ green innovations, but it will also aggravate the decoupling phenomenon of suppliers’ green innovation quality. Additionally, heterogeneity analysis reveals that customer environmental disclosure more effectively promotes supplier’s green innovation for customers with higher transparency and less negative coverage, suppliers with richer structural holes in director networks , and supply chains in the same heavily polluting industries as well as with a long period of cooperation. Overall, the findings suggest that firms should improve their green transformation strategies by leveraging supply chain spillover effects, with a particular focus on customer environmental information disclosure, to establish collaborative mechanisms across the supply chain and optimize green supply chain management.