Abstract: Due to sharply increase on quantity and volume of product data in product design processes,enterprise must improve management on those product data. In spite of depend on different point of view of product data management,various product data management system is developed,but still some basic characteristics they have is similar,it is proposed that several principles would be satisfied in developing product data management system. Because PDM (Product Data Management) is to integrate and management data information which relate developing product,it is crucial to studying the model of information management in PDM for realizing a PDM system. This paper proposes PPOR model,respectively reference product information management model,process information management model,organization information management model and resource information management model. These models correlate each other. They are all described by EXPRESS-G language,and applied in a prototype system based on STEP.