With the rapid development and extensive application of the Internet, Internet users have become increasingly demanding for services. At the same time, developers have also become increasingly demanding on code reuse and loose coupling of application services. Web services provide a solution to these problems. The traditional matching of Web services mainly based on keyword, lacks support for semantic. Thus, it has a less efficiency when used on Web service discovery. In this paper, semantic concept is first used to express the descriptive content of Web services. For the ambiguity between the concepts, a cycle matching method is then presented to calculate the similarity between the concepts, and to ultimately determine the similarity between requested service and advertising service. Finally, the proposed policy is proved to be feasible and effective via experiments.