To counter deficient medical knowledge sharing and the lowefficiency cooperative diagnosis between doctors, the knowledge flow from knowledge management (KM), knowledge acquisition and knowledge supply are established as the core infostructure of a hospital KM model. This is done by combining heavy idea exchange, frequent updating, and intensive use of the medical knowledge. Three important knowledge flow(KF) operations (knowledge refreshing, knowledge migration and knowledge expansion) are proposed. By comparing hospital information management with hospital KM, a hospital KM method based on knowledge flow is constructed. The method emphasizes tracking, monitoring and controlling hospitalwide comprehensive process of medical knowledge. A specific clinical diagnosis instance is given for detailed healthcare knowledge flow analysis. 