Abstract:Knowledge spillover is an important motive mechanism for Industry-University-Research Institute collaborative innovation, which greatly affects the performance of collaborative innovation. On the basis of combing the theory of knowledge spillover, this paper analyzes the siphon effect, funnel effect and polarization effect of Knowledge Spillover of Industry-University-Research Institute collaborative innovation in the three cases of Haier Group Knowledge Alliance, Ofo Shared Bicycle Research and Development Alliance and Huawei Industrial Park. It is found that the three effects of knowledge spillover are often coexisting. It is both an opportunity and a risk to the Industry-University-Research Institute, and the core enterprise is extremely important to stimulate the knowledge spillover effect. And put forward the policy enlightenment from the three aspects of constructing appropriate intellectual property protection mechanism, cultivating social capital development and reforming government science and technology management function.