Binary refrigeration compressor is the critical equipment of ethylene plant. This paper mainly analyzes the causes of the vibration of steam turbine of binary refrigeration compressor in ethylene plant, and uses condition monitoring software to determine through frequency and map analysis that the fundamental causes of vibration are the poor dynamic balance of rotor and the high exhaust temperature. By taking some measures such as replacing the spare rotor after returning to the plant for dynamic balance and using continuous water spray to control the exhaust temperature, the abnormal vibration of the steam turbine is eliminated, and the installation and commissioning of the binary refrigeration compressor are carried out as planned.