Complex Products and systems (CoPS) are by an innovation network developed, in which the flow, diffusion and application of knowledge and information can be facilitated by Inter-organizational Knowledge Management (KM). However, most research of KM focused on how to manage knowledge within an organization, paying little attention to KM on inter-organizational level.  Related literature was reviewed briefly.   The barriers to interorganizational KM inter-organizational innovation were studied through a questionnaire survey.  It is also pointed that the barriers to KM in CoPS innovation may be various in different industries.