Supply chain stability is an important foundation for smooth national economic circulation. Incorporating embeddedness theory into the supply chain research framework, this paper examines the impact of supply chain social ties on suppliers innovation and discusses the mechanism and boundary conditions. The results show that: supply chain social ties have a promoting effect on suppliers innovation, and suppliers will be more inclined to substantive innovation rather than strategic innovation; mechanism analysis shows that supply chain social ties mainly through trust mechanism and information mechanism promotes suppliers innovation; heterogeneity analysis shows that the positive association between supply chain social ties and suppliers innovation is more pronounced, particularly when suppliers face high financing constraints, belong to durable goods industries, or operate in regions with a poorer institutional environment. The conclusion of this paper helps to discover the informal institutional logic behind China’s supply chain operations, and provides an important reference for building a sustainable and stable modern industrial system.