With the growing number of web services, there arise issues of finding relevant services. But, a web service is typically published by registering its WSDL file and a brief description in UDDI business registries. This limits the search mechanism for web services to keyword based searches. In order to overcome shortcomings of keyword based search, there are several attempts to use clustering or ontology for web services search. However, many weaknesses are remained in these approaches. In this paper, we propose a semantic search engine of web services that can improve the recall and the precision using both the clustering approach and the ontology approach. To this purpose, The experimental results show that our system has higher performances both in the rate of recall and precision compared to the existing method.