The design of highly complex engineering systems often involves several different disciplines. The methods of multidisciplinary design optimization(MDO)provide the framework for solving design optimization of complex engineering systems,it is regarded as an effective and prospective solution to complex engineering systems such as airborne electronic equipment system,which contents large number of disciplinary and subsystem,the coupling affections between the disciplinary must be considered in the procedure of design. It improved the Simultaneous Analysis and Design method,builded the appropriate design environment. And the basic structure of the electronic equipment PCB level module is optimized as an example. The results showed that the vibration and thermal performances improved obviously,testify the feasible of this optimization method.