Distributed systems are promisingly used in context of cross organizational enterprises. To develop these systems, Web services form an essential and wide accepted technology because they provide a significant level of platform independency and autonomy. Services are generally designed to interact with other services to form larger applications. In order to interact correctly with each other, Web services have to be compatible. This include not only composability of the involved services but also the correct execution of the overall composite service. In this context,we suggest in this paper to study the compatibility of Web services in different aspects and to provide a formal approach to characterize and verify this property. This approach is straightforward since it combines Petri nets and model checking techniques.