Abstract: In order to represent fuzzy Ontology,this paper extends existing Ontology Web Language(OWL), which can only represent certain and complete concepts and knowledge at present,by encoding fuzzy constructors,axioms constraints and maps semantics of new vocabularies to fuzzy description logic.Moreover,the paper presents mapping rules from OWL to new vocabularies named fuzzy Ontology Web Language(FOWL). At last,the paper gives an example of image retrieval to show representation and reasons of fuzzy Ontology in FOWL form.