Abstract
Semantic web service, with semantic information being added into traditional web service descriptions, can make computers understand contents on the web automatically, thereby supporting the auto-discovery, implementation, monitoring and composition of web services. OWL-s is the description language of semantic web services, but it did not provide a detailed definition for Qos (Quality of service) evaluation, which is the foundation for the selection process of services. In this paper, an evolution model of semantic web service is proposed considering with its semantic characteristics. The model can help to improve the smartness and precision and effectiveness of web service auto-discovery and selection.