In this paper, a hierarchical semantic service case is outlined, which supports overall description of functionality, behavior restraints and features. An adaptable similarity degree measurement is proposed to retrieve a service case which is more similar to the target case and easier to be revised if necessary. Moreover, a method based on the interaction ontology is presented to realize dynamically revising service case to support Web service composition. The method of Web service composition proposed in this paper is proved to be feasible and effective by examinations.