Ultralow temperature of －40 ℃～－80 ℃ is mainly used in the fields such as food processing, petrochemical industry, biological pharmacy and scientific experiments. The ultralow temperature refrigeration system and the research progress with refrigerant and compressor were introduced. Based on the comparison with the current research at home and abroad. the future development of ultra-low temperature refrigeration unit can be optimized from the auto-cascade refrigeration system, and the natural refrigerants as a substitute can also be concerned, further studies for the compressor inverter technology and other aspects of CO₂ compressors’ performance.