In the process of introducing ERP system, in order to enhance the chance of success and speed of the reengineering process, the firm should efficiently utilize its existing information. How to efficiently use existing information in transforming a corporation's information system is an important subject in information system reengineering. The purposes of this paper are two folds. First, this paper intends to investigate how to integrate information system reengineering technology in the process of introducing ERP system; Second, to avoid possible problems of database transfer and conflicts of new and old processes, this paper further investigates on both the subjects of data and process in information system reengineering technology.