In this e-commerce era, Enterprise Resource Planning (ERP) has been viewed as the entering cost for conducting the business and establishing contact with others. ERP system is very expensive and enormous complex package software, and applies the best business practice with partial adjustment and integration to suit for the operation of different enterprises. But due to the characteristics of high investement, high complexity and high risk of failure of ERP systems, misfits have been one of important issues for the implementation of ERP systems. Therefore, the selection of an appropriate ERP system has become the key factor leading to the eventual success of an ERP system implementation. And we select an appropriate ERP system by studing a case that uses ELECTRE I as evaluating tool. This paper first identifies a set of evaluating criteria based on the extensive literature review and the considerat5ion of the environment and characteristics of ERP systems. Once the list was generated, an iterative process of personal interview with the consultant, suppliers, users and managers was conducted to modify the evaluating criteria in order to insure the integrity of it. The result of this study is not only can contribute to the understanding of the functionalities of an ERP system, but also can provide a practical guideline for the selection of an ERP system.