In view of the bearing failure during the operation of compressor,the bearing fault was diagnosed through bearing state parameter detection and oil monitoring.Fourier infrared spectroscopy and scanning electron microscopy were used to analyze the foreign matter that caused the equipment failure.It is concluded that the main component of the foreign matter is organic acid ammonium compound,which is formed by the reaction of leaked ammonia and acid rust inhibitor in lubricating oil.The formation of organic acid ammonium compounds leads to equipment overheating and the product of varnish,resulting in bearing temperature rise and vibration intensification.The bearing fault solution was put forward,the influence of varnish was eliminated,and the operation stability and safety of the compressor were improved.