Abstract: Exceptional rules may be exceptional information of information systems, these exceptional information is as important as those of normal information in modern times. This paper summed up much shortcoming of many algorithms of processing incompatible rules and presented a correcting algorithm of incompatible rules based on entropy. According to confidence which the paper assigned,it can judge whether rules of information system are exceptional rules.An example was given to demonstrate the main idea of this algorithm.

Key words: Incompatible rules, Exceptional information, Entropy, Exceptional rules