The TAE-100A/30 centrifugal compressor of the air compressor station in the Ethylene Plant of PetroChina Dushanzi Petrochemical Company is mainly used to provide coke cleaning air for the old chemical plant area. During operation, the compressor experienced a secondary interlock shutdown and failed to start up again after interlock reset. The causes of the interlock shutdown of the compressor were analyzed, and the primary, secondary and tertiary cylinders of the compressor unit were repaired. The main cause of the failure was the fatigue fracture of impeller during the long-term operation of compressor. Some preventive measures were developed to ensure the long-term operation of the compressor unit.