The multidisciplinary design optimization(MDO)approach is very crucial for the conceptual design of the aircraft,and this is due to the complex interaction between different disciplines, especially for the hypersonic vehicle. In the hypersonic vehicle, the airframe and the engine are highly integrated. In the current survey, the research progress in the MDO approach has been reviewed comprehensively from four primary techniques, namely the design of experiments, the surrogate modeling, the optimization method and the MDO framework, and its application to the aerospace engineering has been summarized from its category as well. The concurrent subspace optimization approach is the most popular method in the aerospace engineering for its easy implementation, and following is the collaborative optimization approach. The multi-level optimization approach has attracted a growing attention due to its high efficiency. In conclusion, some promising research recommendations have been put forward, namely the combination of the low- and high-fidelity optimization approaches, the consideration of the uncertainty analysis and the MDO approach coupled with the data mining techniques. The multidisciplinary design optimization (MDO) approach is very crucial for the conceptual design of the aircraft, and this is due to the complex interaction between different disciplines, especially for the hypersonic vehicle. The hypersonic vehicle, the airframe and the engine are highly integrated In the current survey, the research progress in the MDO approach has been been reviewed comprehensively from four primary techniques, namely the design of experiments, the surrogate modeling, the optimization method and the MDO framework, and its application to the aerospace engineering has summarized from its category as well. the concurrent subspace optimization approach is the most popular method in the aerospace engineering for its easy implementation, and following is the collaborative optimization approach. The multi-level optimization approach has attracted a growing attention due to its high efficiency. In conclusion, some done research recommendations have been put forward, namely the combination of the low- and high-fidelity optimization approaches, the consideration of the uncertainty analysis and the MDO approach coupled with the data mining techniques.