Parts (and components) family is presented to realize another information expression method for the tabular layouts of article characteristics, and given a uniform and formal definition, including the template model, the attribute set and the family member. The principles and methods of grading to construct components family is discussed, which components, sub-assembly and parts are described with associated attributes in their respective levels. The links between components, subassembly and parts are established through member attribute, reducing attributes number of components and subassembly, reusing parts library, and achieving efficiently for building components library. For an example, the reuse library of diestamping components is established for the mold design.