To overcome the shortcomings of the traditional document methods used in the design of the integrated avionics fire control system,with the aid of the model-based system engineering theory,a method for object-oriented graphic system design based on Rhapsody is proposed.The specific design procedure and implementation steps are given.Taking a typical combat process of a certain aircraft for instance,this paper studies the application scenario and usage of various legends in the design of Rhapsody graphic system in detail,connects the legends in each designing stage with each other through function transference,and works out a complete design method for complex system.This method can realize the iteration optimization of the system,reduce workload and shorten the development cycle,which can serve as a reference for the graphic design of complex systems in the future.