Abstract: Part family modeling based on structure-view model is introduced in this paper. The model describes the object level of part variable design as a structure, possessing certain engineering context and engineering functions. In this paper, the part is described as an expandable net, composed by functional structures in certain combination relations. The part is build-up by structures in the way of adding the layout and combination restriction. Modification of parameters can lead to the change of the actual part size, and the modification or substitution of the structure can lead to the derivation and change of the actual part. It may raise the object level of the part variable design and implement the variation of the part structure.