is more applicable for representing vague information since it provides a way to control a degree of hesitation.One of most prominent research direction on the theory of IFS is measurement of similarity between IFS.Even several similarity measures have been proposed,some unreasonable cases can be made by such measures.In this paper,we present two similarity measures: one is a set-theoretic measures, the other combines the former measures and the concept of similarity measures on a concept lattice.In our experimental study, we focus our attention on two basic directions of performance evaluation: