This paper describes parameter check methods and their representation model in product design process. Conventional mechanical CAD systems have some geometric check functions on dimention, mass property and PDQ (Product Data Quiality). But these rules are available in only one CAD system and their scope is limited, so it is difficult to use them as synsetic rule checker between several systems. For integration of design rules, we have studied design rule representation model of high visibility and generality. Our proposed model describes the rules as simple scripts using part structure and the relationship between parameters of part attributes. We implemented our model in an independent prototype from CAD system, and have verified practical effectiveness of it.