This paper discusses the problem of excessive axis displacement of intermediate pressure cylinder occurred during the long-term operation of cracking gas compressor in the 640 kt/h ethylene plant at Sinopec Maoming Petrochemical Company. Based on the analysis of possible causes of the axis displacement failure, some measures were taken such as adjusting the process system, optimizing the injection of wash oil, adjusting the lubricating oil system, injecting water into the intermediate pressure cylinder and adding dispersant. These measures reduced the axis displacement to a certain extent, especially when the operating load was reduced, the axis displacement decreased significantly. However, none of these measures could completely solve the problem of excessive axis displacement of intermediate pressure cylinder. By injecting the mixed solution of aviation kerosene and polyethylbenzene as the wash oil, a large amount of fouling substance was dissolved and flushed out, completely solving the problem of excessive axis displacement caused by cylinder fouling.