Abstract:The dependent relationship among Web Services is the key of behavior modeling supporting automatic Web service-oriented composition. Based on the historic data of the service allocation, an approach finding the dependent relationship among Web Services was deducted and reasoned through fixed points, the method of building up the behavior modeling of Service composition based on the map model was given, also the calculating way of producing the guides of service composition was proposed. The experiments showed that, in a certain amount of data, the above behavior modeling appeares linear changes, so the approach proposed is feasible and effective, which could be as technical support of automatic Web service-oriented composition.