Through the analysis of the inter-stage pressure difference and polymers in charge gas compressor of ethylene plant, the problems affecting long-term operation of the charge gas compressor in the No.2 ethylene plant of PetroChina Jilin Petrochemical Company were identified. Hot tapping was carried out for the pipelines of the inter-stage heat exchanger of charge gas compressor, and wash oil injection, dispersant line and nozzles were provided. The inter-stage heat exchanger of the charge gas compressor was cleaned by injecting washing oil and dispersant to reduce the polymers in heat exchanger, reduce the inter-stage pressure difference in charge gas compressor, and prolong the operation cycle of the compressor.