Abstract
Along with web service composition becomes more and more complexity, design of composition process becomes more and more error-prone. In this article we put forward a WSC_ECPN model for web service composition description based on extended colored Petri net. This model is independent of any concrete process description languages, supports process description and can describe composition process more comprehensively. Moreover, we present methods to analyze control flow correctness, data flow correctness and process instance correctness of the composition process, thus we can insure process correctness from these three levels. It the end we give an example to illustrate the application of WSC_ECPN model.