Web services composition is becoming very important in today's service oriented business environment. Different services frequently have semantic inconsistencies which may lead to the failure of the services composition. In order to verify the correctness of the Web Services composition, we present a method for analyzing and verifying interactions among web services. We model web service composition based on special class of Petri nets: open workflow nets. We translate this composition to Promela, a source language of SPIN model checker, designed to describe communicating distributed services. At the requirements level, model checking is used to validate the specification against a set of formulae specified into LTL which are used to verify constraints satisfaction of web services composition.