A product structure model based on the assembly topology tree is put forward. Based on this, the object-oriented product model classes are built up. By using tabular layouts of article characteristics technique, the transformation from part classes to part examples is realized, so the variant design of product can be carried out. Associated with variant rules and tabular layouts of article characteristics technique, aircraft tooling’s fast design system on the CATIA V5 software platform is used in a large aviation enterprise. And a case illustrating practicability of product variant design is verified.