Abstract: The open innovation paradigm brought forward by Henry Chesbrough offers a new way of thinking and managing about innovation. Based on the survey data from 209 innovative firms in China, the mechanism of open innovation is verified by Structural Equation Modeling(SEM). The research manifests that enterprises acquire market-related resources and technology-related resources to complement the internal innovation resources and improve the efficiency of innovation through open to outside. The each innovation key element promoting the innovative performance under an open innovative system is disclosed. And it also gives a good directions for enterprises to increase indigenous innovation capabilities through utilizing external knowledge effectively according to their internal innovation resources.