Abstract: In view of problem that current lubricating oil temperature monitoring method of emulsion pump can only identify oil temperature overrunning but cannot monitor abnormal temperature rise, an oil temperature monitoring method based on statistical process control was proposed according to statistical properties of oil temperature process data, and an implementation scheme of exponentially weighted moving average control chart applied to oil temperature monitoring was given. On the basis of the scheme, an oil temperature monitoring system of emulsion pump was designed. The practical application results show that the system can monitor oil temperature of emulsion pump in real time and send out fault alarm accurately.