Abstract: The aerospace industry is very important due to its characteristic of dual-use. The aerospace industry is facing greater difficulties in terms of sustainability of both resource input and market expansion than the early years. This paper defines the aerospace industry's sustainable development capability, and its connotations are analyzed from four aspects. On this basis, the aerospace industry sustainable development capability assessment index system is constructed, consisting of 15 indexes whose weights are obtained by using the AHP method. With this index system, the sustainable development capability of China's aerospace industry from 2012 to 2018 is assessed by using the method of grey fixed-weight clustering where grey classes including High, Medium, and Low, and it is found that the sustainable development capability of China's aerospace industry belongs to High or Medium grey classes, but the problems of industrial ecology and industrial system flexibility are rather prominent. Accordingly, some suggestions are put forward.