Abstract: Importance of ontology is being recognized in a various research and application areas,including knowledge engineering,database design and integration,information retrieval and extraction,software engineering,and natural language processing. Especially its application in the World Wide Web,which leads to the semantic Web,shows an attractive solution to share Web information with awareness of semantics. A survey of recent research efforts on ontology in computer science is presented. It includes the origination and development of ontology,the definition of ontology,ontology description language,ontology construction methodology,semantic Web,and ontology applications.