This study aims to develop a translator for coexistence of VAN EDI and XML EDI methods in an e-Commerce system. The electronic documents are translated in two steps. At the first step, the translation is performed in the conceptual level. The EDI standard is translated to XML schema. The stage includes the class diagram modelling of EDI standard using the extended mechanism of UML and the following translation to XML schema. And, at second step, the definitive translation is performed. The contents of documents are translated each other for EDI and XML documents. In this step, the information necessary for contents translation is extracted from the XML schema created in the first step, and then the mapping table is constructed using the information. The document translation is completed by this mapping table. A translator developed by this study is superior to the existing flat file mapping method, in terms of maintenance and expansion.