Because XML is a W3C standard and has characteristics like platform-independent, it has a critical role in e-commerce. Business rules and procedures should be standardized for efficient B2B integration. But a lot of companies has its own XML documents instead of standard documents. Therefore many organizations try to make standards for e-commerce based on framework. In this paper, n messaging system is designed and implemented. Client request service in a XML and server return response in XML in this system. So we can more easily and efficiently build e-Procurement system based on this XML messaging system.