Abstract: The Comprehensive Research Facility for Fusion Technology（CRAFT） cryogenic system plans to build four helium refrigerators and several cryogenic key technology research platforms. 200 W@4.5 K helium refrigerator, as one of them, will be built to provide testing conditions for a material performance research platform. Through the analysis of the process flow, it has been clarified the control process of helium refrigeration machine liquefaction mode of 200 W@4.5 K. The 200 W@4.5 K helium refrigerator control system is designed and developed based on CODAC control system. The specific network architecture and software design are provided, as well as the design and implementation of the compressor automatic control process and control loop in liquefaction mode. The operation results indicate that the designed automatic control program can effectively complete the load increase and pressure control during the compressor start-up process.