Abstract: Seal dama ge and sealing oil contamination are serious in the gas compressor of ARGG unit in Yueyang Petro-chemical Plant and the safety of the production facilities is endangere d.Several measures such as replacing sealing gas were implemented to control le ak of sealing system of the gas compressor.Quality deterioration of sealing oil in the oil tank was effectively prevented,and the flash point was kept withi n the required limits,thus safe operation of the unit was ensured,and abnormal shut down was successfully avoided.