The applications of IDEF0 method in military integreted information systems analysis, design, updating, integration, and simulation are discussed in detail. For IDEF0 model is simple but comprehensive, and with powerful ability in system description, it is widely applied in various fields, especially in manufacturing. Military integreted information systems, based on information and supported by activity, are large and complex systems. With IDEF0 model, the common understanding of the systems both for the military commander and the technical engineers can be deepened. So it can improve the effectiveness and practicability of development of the military integreted information systems.