Abstract
Existed methods for automatic web services composition based on output parameters and input parameters matching relations of services are limited to linear or tree composition plan and malfunction to the netty plan because they ignore relations between services participating in composition. In order to overcome the shortcoming of the existed methods, a new method is proposed in this paper. In this method, services composition is modeled as a directed graph, and the maximal services composition graph is constructed first, then all the minimal composition graphs will be abstracted from the maximal one by the shared nodes in it. This method can deal with linear/tree/netty composition plan because it finds out not only all services participating in composition, but also all relations between services. All composition plans can be acquired for user to choose by using this method.