Abstract: How to acquire the optimal attributes reduction and weighs of attributes in incomplete information system is a hot topic for researching in rough sets theory recently. A rough set analysis method based on tolerance matrix and principle component analyze was provided in incomplete information system, which is one of heuristic data analyzing methods. Corresponding algorithm and an example were also given in this article. hhe method provided in this paper was compared with other methods. The result shows the method provided in this paper can find efficiently the core of an incomplete information system and acquire weighs of attributes through quantitative analyses.

Key words: Tolerance matrix, Principle component analyze, Rough sets, Attributes reduction