Rough set theory is mainly used in attributes reduction and classification . potential rule , internal relation of inaccurate or noise data can be discovered by rough set , although there is no any prior knowledge expect the data set associated with actual problem 粗糙集理论无需提供除问题相关的数据集合外的任何先验信息,适合于发现数据中潜在的规律、不准确数据或噪声数据内在的结构联系,可以解决重要的分类问题。