Based on the analysis of the shortage of current CIM(Common Information Model)in power system, this paper designed a visual ontology editor of power domain. It could translate the description language of CIM from UML to OWL DL(Web Ontology Language based on Description Logics). Experimental results indicate that the editor can complete the CIM language translation from UML to OWL DL and the translated- ontology can be well inferred by machine and be extended intuitively.