Based on the study of decision content for materiel support and command aided support system, a modeling method for complex system is put forward. Firstly, the process of materiel support activity is described by using IDEF3 method and decision problem on materiel support activity is summarized. Secondly, the IDEFO function modeling for aided support system is established. Finally, the method of establishing information model and dynamic model is pointed out. The establishment of model becomes a stable foundation for the follow-up development.