In order to strengthen the management of natural gas compressor，three class oil monitoring system was established in Sulige Gas field,in which the second class oil monitoring system played an important role in the management of natural gas compressor.Three class oil monitoring system provides an effective method for the management of natural gas compressor,it lays the foundation for the fault diagnosis,prolonging the oil change period,reducing the repairing cost,and ensuring the safe and reliable operation of the natural gas compressor.