Because XML is a W3C standard and has characteristics like platform independent, it has a critical role in electronic commerce. Many electronic commerce systems are already using XML. Business rules and procedures should be standardized for efficient B2B electronic commerce. But a lot of companies have its own XML documents instead of standard documents. In this paper an XML message processor is designed. Clients may request services in XML and server returns response in XML in this system. This XML message processor can be applied easily and used efficiently in electronic commerce systems.