The semantic web was proposed as the next generation web technology. In the environment of the semantic web, resources as well defined and related with each other semantically. the RDF supports this basic mechanism. To establish and develop the semantic web, the basic technologies related to RDF data must be pre-established. In this research, we develop methods for storing and querying RDF data using an XML database system. As using XML database, XML data and RDF data can be integrated and efficiently managed. We construct and evaluate a system applying the proposed method to store and search data. we compared the query processing performance on our system with that of an existing system. The experiment result show that our system processes queries more efficiently.