In this paper we propose a new similarity measures in order to overcome some problems in [1],and proposethe idea for similarity direction of vague sets by which to describe which one is more accurate between vague sets. Atsame time we propose a method to determine the similarity direction. Based on above,we present a new bidirectionalapproximate reasoning approach on vague set that fully uses the message accuracy of vague set. So this improves theaccruacy and applicability of approximate reasoning. This provides a useful tool for approximate reasoning in intelli-gence system.
