Cracking gas compressor is the core equipment of ethylene plant, and the stable operation of the compressor unit is crucial to the continuous and safe operation of ethylene plant. This paper focuses on the overhaul items of cracking gas compressor and turbine in the 1000 kt/a ethylene plant at PetroChina Dushanzi Petrochemical Company and the problems emerged during overhaul, analyzes the causes of the problems based on process operation data, and puts forward some overhaul control measures and problem solving measures.