The performance of SOAP is lower than that of existing distributed object technologies such as RMI and CORBA, because SOAP needs extra process parsing and building message to process an XML document. Therefore, performance improvement for SOAP processing is challenge to apply SOAP to a high-performance system. In the case that we focus on SOAP message features, we notice a SOAP message format is pre-defined for each service program and the format does not change while the system is running. A little part of a SOAP message is variable and the rest that includes tag description is invariable. In this paper, we focus on the above features and we create a template from a SOAP message format. Our approach parses a SOAP message by analyzing differential between a SOAP message and the template. Our approach improves the performance to improve lexical analysis and validation while processing an XML document.