CA（Controlled-atmosphere）freshness cold rooms are the most advanced fresh-keeping method for fruit and vegetables.On the basis of refrigeration, it can modify the gas components. By controlling the temperature, humidity, CO2, 02 and ethylene concentration in the rooms, the CA cold room inhibits the respiration of fruits and vegetables,delays their metabolic process, and better maintains the freshness of fruits and vegetables, and prolong the storage period and fresh-keeping period(sale shelf life) of fruits and vegetables. The fruits and vegetables stored in the CA freshness cold rooms will wake up from the dormant state after leaving, which makes the fresh-keeping period(shelf life) extended by 21-28 days, which is 4-5 times that of ordinary cold rooms.