[Abstract] Since 1990s, the development for civil aircraft has been improved qualitatively, and the model of product development based on digital mockup (DMU) has become mainstream. DMU modeling and simulation technology begin to show their support role in the development of civil aircraft. At the same time, based on the requirement of aircraft development, DMU modeling and simulation technology have made remarkable progress, and the application of the aircraft continues to extend and expand. The design process and key technology of DMU modeling and simulation in the process of aircraft development are discussed and summarized in this paper. The design process and key technology are good references to the development of other civil aircraft DMU.