Due to the lack of overall understanding of the content of aircraft system synthesis design, the aircraft development departments cannot conduct an effective working plan in advance, which always causes rework problems. To solve this problem, a review is conducted on the synthesis design of aircraft systems in engineering, and the synthesis design process of aircraft system based on system engineering is proposed; the comprehensive design content of aircraft system is comprehensively deduced. These synthesis design content can provide beneficial reference for aircraft development departments, such as conducting an overall working plan on the aircraft level system synthesis design, and finally help the design engineers to realize the target of “cost reduced and quality improved”.