The process flow characteristics of the No.2 cracking gas compressor (GB1201) in ethylene complex in the Olefin Plant of SINOPEC Yangzi Petrochemical Co., Ltd. are introduced. By summarizing the steam consumption and the work done by cracking gas compressor turbine and the compressor efficiency, the relevant factors affecting the first-stage suction pressure of the cracking gas compressor are analyzed, the reasons for the high first-stage suction pressure are identified and some improvement measures are proposed, providing operational guidance for the long-term and efficient operation of the cracking gas compressor.