This paper briefly describes the revamping content and purposes of the control system for three key compressors in ethylene plant, and introduces the operating conditions and steps of the new system after revamping. The new system focuses on unit protection and anti-surge, and over-speed protection, unit status monitoring and unit interlock protection (emergency shutdown system) are combined into one set of ITCC system, providing a safe and reliable operation platform for production. The performance of the control system for three key compressors has been improved, the functions have been further improved, the operating load has been reduced, the comprehensive control and operation of the unit has been realized on the integrated operation interface, and the operating efficiency has been improved.