Multidisciplinary design optimization (MDO) is regarded as the most hopeful upgrade of current methodology for complex system design.  In order to overcome the difficulties in advanced aero-engine design,  such as complex coupling relations and serious conflicts between different disciplines,  the research,  development and application of key technologies of MDO have been carried out in three phases: part design,  component design and whole engine preliminary design.  And a MDO-based integrative aero-engine design method is presented.  Five examples of engineering applications are given to demonstrate that the proposed method can improve aero-engine design ability very much comparing with the traditional method,  and is prospective to be applied widely to engineering field.