Corporate environmental responsibility is an important component of corporate social responsibility. Based on data from Chinese listed companies from 2010–2018, the relationship between the two was explored using a fixed-effects model, with the supply chain net cash ratio being used as a proxy variable for supply chain power. This study found that supply chain power has a significant positive impact on the environmental responsibility of upstream suppliers and downstream customers. There is a vertical spillover effect of supply chain power on corporate environmental responsibility. A stepwise regression approach was used to investigate the mediating effect of business performance between the two, and the bootstrap method was used to test the existence of the mediating effect. Firms can use their power in the supply chain to reasonably allocate profits in the supply chain, which not only helps them to fulfil their environmental responsibility but also influences other firms in the supply chain to fulfil their environmental responsibility.