Maintaining stable supply chain relationships and facilitating the smooth flow of innovation elements are the core drivers of innovation performance improvement for SRDI (specialized，refined，differential，innovation) enterprises. This study uses A-share SRDI listed firms from 2015 to 2024 as the research sample and examines the impact of supply chain relationship stability on their innovation performance from the perspectives of suppliers and customers. The results show that supply chain relationship stability significantly improves the innovation performance of SRDI enterprises，mainly through enhancing their absorptive capacity and risk-taking ability. The moderating effect analysis shows that supply chain concentration weakens the positive effect of supply chain relationship stability on innovation performance. Further analyses reveal that the positive effect of supply chain relationship stability is more pronounced in firms facing higher financing constraints，greater supply chain risks，or operating in high-tech industries. Moreover，the impact of supply chain relationship stability on enterprise innovation performance is asymmetric. This study broadens the theoretical understanding of how supply chain management enhances innovation performance，providing theoretical reference and empirical evidence for SRDI enterprises to deepen supply chain collaboration and achieve high-quality development.