关键词: 粗糙集, 区分矩阵, 属性约简, 浓缩树

Abstract: Attributes reduction is one of important parts researched in rough set theory.This paper weights the frequency of the attributes in the condensing tree，and combines with the heuristic method of the attributes’ frequency weight，takes the core as foundation，deletes the most important attributes in the tree until the tree is null；in order to find optimum reduction of information system，the paper adds the converse eliminate action until cannot delete.A demonstration is given at last in the paper，and it verifies the method validity.

Key words: rough set, discernibility matrix, attribute reduction, condensing tree