Study on knowledge flow network is to realize the effective knowledge passing and sharing. Well-planed knowledge flow network can build smooth knowledge channel for geographically distributed virtual organization, reduce knowledge passing redundancy, and improve the efficiency of knowledge use and creation. This paper studies the characteristics and principles of knowledge sharing and creates a loosely coupled market-based knowledge flow networks to improve the efficiency.The content of this paper focuses on the following issues. First of all, this paper proposes knowledge energy as a factor to reflect the knowledge possession and the creative ability of nodes and explores the assessment methods and the principles about knowledge energy. Second, it discusses the trust relationship in knowledge flow networks and gives a trust model. Then, for the absence of incentive to sharing knowledge, this paper proposes a market-based knowledge sharing environment by utilizing auction and bargaining mechainism. After the transaction, the knowledge energy flows from the higher energy node to the lower one and the trust relationship between nodes is enhanced. Market-based knowledge flow network can realize effective knowledge sharing and trust building, can arouse the enthusiasm of nodes for taking part in the knowledge sharing, and can benefit both individual advantages and organization creation. Simulations have been proposed to prove the performance and characteristics of market-based knowledge flow networks.