Web service constitutes a new computing model for Web application. The application based on SOA is a promising trend of distributed computing. However, currently Web service system, which uses centralized UDDI to publish and discover Web service has become the bottleneck of the whole system. In addition, Web service description based on WSDL cannot support discovery at a semantic level. Therefore, we propose a fully decentralized and interoperable discovery method. P2P network is used as the basis network to replace traditional UDDI. At the same time, we take advantage of OWL-S to add valuable semantic information in Web service description. By introducing domain ontology, we implement the classification of the service domains. The experiments have shown that this distributed approach guarantees the scalability and robustness of the discovery system. Discovery precision has been improved as well.