The traditional maintenance of large fixed equipment delays the best time to repair, with maintenance problem, large fixed equipment online monitoring and fault diagnosis system was introduced, the ventilator and belt conveyor were taken as an example, the actual application effect in mine large fixed equipment was discussed. The result showed that the monitoring system could conduct intelligent quantitative diagnosis analysis to the possible damage of the equipment, realized diagnostic report generating automatically, whole life cycle track and remote control etc., and position the precise fault part of the equipment, reduce the blindness of equipment repair and ensure the safe operation of large fixed equipment in mine.