Abstract: After briefly introducing the PDS products of Intergraph Coporation of America, this paper analyses PDS data structure and the working process of piping component placement in detail. According to the situation that the PDS database is American English system,this paper makes a change it to metric system, and also provides detail methods for all data files related to English and metric system, that is piping materials class data files, piping specification data files, piping job specification database and physical commodity data library.