Innovation is more and more important for enterprises or most of organizations, but the results of many innovation activities are not satisfied. We find that the reason lies on insufficient knowledge management which can not supply systematic knowledge to support the requirement of innovation. Even worse the lacked knowledge is seldom been aware of. By studying on the Extension Theory (Extenics) and web intelligence, we proposed a novel knowledge management methodology called Intelligent Knowledge (IK) management. It can integrate knowledge from different sources such as human experience, the web or data base and construct a systematic knowledge map for product innovation. It gives a way to compensate the limitation of human knowledge and help people to find more ideas based on all-direction knowledge supported by information technology and Extenics. Its application in an electric company shows that IK-based product innovation is a useful model.