This paper takes A share listed companies from 2012 to 2020 as samples to investigate whether the game competition among suppliers can influence the innovation activities of downstream enterprises. It is found that supplier competition promotes enterprise innovation. The results of mechanism analysis show that supplier competition improves enterprise innovation level by alleviating business risk, financing constraint and improving supplier innovation spillover. Further testing the heterogeneity of suppliers and enterprises shows that the more suppliers with high technology background, the higher the stability of suppliers, the stronger the product market competitiveness of enterprises and the disclosure of suppliers’ rights and interests protection information, the more obvious the positive promoting effect of supplier competition on enterprise innovation. The conclusions enrich the research perspective of supply chain relations, and provide empirical evidence for enterprises to improve supplier selection mechanism, develop differentiated supplier strategy and improve their own innovation ability.