For the requirements of knowledge reuse in product design process, according to the characteristics of the knowledge representation methods, this paper uses ontology knowledge representation method to construct the product design process knowledge model and gives ontology mapping decision strategy which is based on classification. In the basis of choosing "design department" ontology in human resource management as the heterogeneous ontology of "design organization" ontology in product design process management, lists their concepts set and calculates the similarity of matching concept pairs, finally, outputs the mapping relationship table.