关键词: Vague集, 相似性度量, 基本准则, 一般方法, 未知度

Abstract: This paper firstly analyses two main sorts of similarity measures between Vague sets and between elements at present，and points out the same problem of these measures.Then，some basic rules are proposed to measure the rationality of similarity measures.According to the basic rules，a new method of similarity measure is introduced in general conditions，which takes full advantage of the hesitancy degree of element.The necessary conditions of this similarity measure are also pointed out.Finally，the application of the similarity measure and its effectiveness are illustrated by an example in pattern recognition.

Key words: Vague sets, similarity measure, basic rules, general method, hesitancy degree