Outsourcing knowledge-intensive business service has become an important way for the enterprise acquiring knowledge as the development of specialization and informationization in contemporary production. However, there are some particularities in knowledge intensive services production??C and enterprises have to face unique challenges when outsourcing knowledge-intensive service. This paper starts from analyzing the specialties of knowledge-intensive business service, and outline the decision process of enterprise outsourcing knowledge-intensive service and its motivation. This paper systematically examines the mechanism of collaborative innovation between KIBS and the client.