Abstract: As one of the main auxiliary equipment in power plant, the normal and safe operation of fan directly affects the economic situation and normal operation of power station.However, the relevant monitoring technology and fault diagnosis instruments in China are not advanced enough, and they are only stuck in the low-level stage of fixed time patrol monitoring, shutdown maintenance and follow-up status analysis. Therefore,in real life, it is often faced with fan detection time has not yet arrived, but the fan fails, resulting in shutdown and other situations, causing serious losses to enterprises.Based on this, it is very important to improve the diagnosis of fan fault system.