Abstract: Both patent applications and patent lawsuits have increased rapidly in recent years. It is necessary to clarify the interaction between them. Co-integration and error correction model are employed to analyze the time series of patent applications and patent lawsuits. It shows that there is a long-term dynamic equilibrium relationship between patent applications and patent lawsuits. The results of Granger causality show that patent applications and patent lawsuits present a significant interaction of mutual promotion. Patent applications have a positive effect on patent lawsuits, indicating that the increase in patent applications will lead to the emergence of massive patent lawsuits in the future. Meanwhile, patent lawsuits also present a positive effect on patent applications, which means that the increase in patent lawsuits will inspire patentees to apply for more patents.