A critical step in the process of reusing existing WSDL-specified services for building web-based applications is the discovery of potentially relevant services. However, the category-based service discovery, such as UDDI, is clearly insufficient. Semantic Web Services, augmenting Web service descriptions using Semantic Web technology, were introduced to facilitate the publication, discovery, and execution of Web services at the semantic level. Semantic matchmaker enhances the capability of UDDI service registries in the Semantic Web Services architecture by applying some matching algorithms between advertisements and requests described in OWL-S to recognize various degrees of matching for Web services. Based on Semantic Web Service framework, semantic matchmaker, specification matching and probabilistic matching approach, this paper proposes a fuzzy-set based semantic similarity matching algorithm for Web Service to support a more automated and veracity service discovery process in the Semantic Web Service Framework.