Abstract: Rotating machinery fault diagnosis was studied based on rough sets theory. Decision table of fault diagnosis is built up form the chart and correlative data of rotor fault experiment, the relation between condition attribute and decision attribute is made out. The simple decision table is gotten, and decision rules of rotating machinery fault diagnosis are formed, and reliability of decision rules is studied on rough sets theory. The reduction and core of decision table are put out by discernible matrix and discernible function, and the simplest reduction modality of decision table can be elected by optimization.

Key words: rough sets theory, fault diagnosis, reduction, core