International supply chain disruption is a major risk that seriously hinders high-quality development of China's economy. We have developed an R&D competition model to discuss the impact of supply chain disruption on firms’ R&D behavior, analyze the welfare effects and effective paths of R&D subsidy policy. This article finds that, supply interruption by foreign suppliers will promote domestic R&D and inhibit foreign R&D. In other words, the market mechanism itself has the effect of narrowing the technology gap between domestic and foreign suppliers. Although the risk of supply chain disruption weakens the competition in the upstream market, which is beneficial to domestic suppliers, it harms downstream market manufacturers and consumers. When the technological gap is large and the proportion of foreign suppliers is high ("stranglehold"), the increase of supply interruption risk reduces domestic welfare. The R&D subsidies based on R&D output may crowd out R&D investment, thereby reducing domestic social welfare when supply interruption risk is low and enhance it otherwise. On the other hand, subsidies based on R&D expenditure have a smaller crowding-out effect and can improve domestic social welfare under the risk of supply chain disruption. The article provides theoretical support for scientifically formulating R&D subsidy policies and fully leveraging market mechanisms to address the risk of supply chain disruption.