To discover the knowledge of fault diagnosis in maintenance record of flexible manufacture system(FMS) equipment. An algorithm (process) was presented, which consists of ① preparatory phase in which some items in maintenance record are selected and decomposed into associated concepts and attributes, and ② discovering and establishing process, in which some possible relationships between the concepts and attributes can be established and knowledge is formulated. The rich diagnosis knowledge in maintenance record was captured through applying the method. An application of the method to the diagnosis system for FMS equipment showed that the approach is correct and effective.