Abstract: Web service matching is an important step in dynamic services composition. However, most current researches only make the local semantic matching for individual abstract Web service during composition process, not taking the global matching into consideration. Moreover, even though the global matching is considered, there is only QoS-aware matching, not global semantic matching. To achieve all these goals, aimed at abstract Web services composition process, the first is to locate appropriate concrete Web services and obtain them. Based on the declarative semantic description of Web services, two steps of matching are proposed. One is a local semantic matching based on the abstract services and the other is a global semantic matching based on QoS-awareness. The semantic matching algorithm is designed for local semantic matching and the usability of service is extended in the algorithm for input/output matching. A QoS model is built and a corresponding evaluation method is given for matching of service composition process. Based on the QoS model and the evaluation method, a genetic algorithm is proposed to achieve the maximal global semantic matching degree and to satisfy QoS requirement for the whole abstract service composition process. Experimental results and analysis show that Web service matching mechanism based on semantics and QoS-aware aspect is feasible and effective.