Abstract: It is rather difficult to analyze and make use of asynchronous sequential circuits, so the application of asynchronous sequential circuits is much narrower than synchronous ones. We have improved the approach of J.R.Burch et al. and make it suitable for asynchronous sequential circuits. New method expresses the transition relation of circuit through Boolean characteristic function based on OBDD(Ordered Binary Decision Diagram). Furthermore, it determines the stable state and next stable state of asynchronous sequential circuits by the operations based on OBDD for the exact description of the property of circuits.