In order to obtain the rule of fault diagnosis of local ventilation facilities in mine and to shorten the time of fault diagnosis,a fault-diagnosis-rule acquisition system based on rough set was studied and developed.In this paper,the structure and functions of local ventilation facilities information database for mine were analyzed.The method of establishing facilities faulty decision-making table and the property reduction technique were discussed.The calculation of a real case shows that this system can well implement the integration of management of historical fault data and fault.Diagnosis rule acquisition.