Mechanism of BPEL access control is one of focal points in Web services secure composition. It is a difficult problem to maintain the activities authorization constraint coordination. With the extended CPN(Colored Petri Nets) for modeling the dynamic behavioral semantics of BPEL activities execution, this paper used the method of coverability tree to analyze the fire sequence of model state transition, and implemented the dynamic consistency detection of activities authorization coordination. The paper provided theoretical foundation for the ...