Abstract: After lubricating oil enters the dry gas seal of natural gas compressor, the oil film may absorb the heat from friction produced in the end face between rotating ring and stationary ring of the dry gas seal and result in damage of rotating ring and stationary ring due to their overheating. Therefore, it's necessary to figure out the reasons for oil entering. According to various possible factors that may cause oil entering and combing with the accident phenomenon, this paper analyses and investigates the reasons. It discovered that the root causes for the oil to enter the dry gas seal were that the lubricating oil pressure was too high and the effect of isolation gas became worse. A full adjustment was made for the header pressure of lubricating oil and oil pressure of thrust bearing and journal bearing of compressor. An attempt to purge the dry gas seal with oil instead of overhaul and replacing succeed. And corresponding countermeasures in management are put forward.