Semantic Web is the next-generation Internet,the Semantic Web Ontology is the realization of Description Logic.In the paper,we present an approach to convert ontology into a relational database schema which stores the instances of each classes and properties in separate tables and uses some views to reflect the relationship between the OWL objects.The proposed converting method has the advantage that it does not require extensive modification of the database structure when changes occur.It is suitable for small and medium-sized ontology change.