Web services are the basic building blocks for the business which is different from web applications. Testing of web services is difficult and increases the cost due to the unavailability of source coder. In previous work, web services were tested based on the syntactic structure using Web Service Description Language (WSDL) for atomic web services. This paper proposes an automated testing framework for composite web services based semantics, where the domain knowledge of the web services is described by protege tool [13] and the behavior of the entire business operation flow for the composite web service is provided by Ontology Web Language for services (OWL-S)[6]. Prioritization of test cases is performed based on various coverage criteria for composite web services. Series of experiments were conducted to assess the effects of prioritization on the coverage values and benefits of prioritization techniques were found.