The open innovation paradigm brought forward by Henry Chesbrough offers a new way of thinking and managing about innovation.Open innovation can speed innovation;reduce the uncertainty of technology and market.It could also provide access to more ideas than could be developed in-house.By leveraging the discoveries of others,companies can produce spectacular results.Too open will bring negative impacts also because of the costs for searching and the leakage of key technology.This paper empirically verifies the relationship between the degree of openness and the innovation performance.We find that the more open in the innovation process,the higher innovation performance would be.This paper finds that the negative impact is insignificant.It is because the degree of openness is not enough for Chinese firms.The ability of using and integrating external knowledge is crucial for Chinese firms to improve the technological innovation capability.