The cold air dryer is a process that uses low-temperature and low-humidity air to forcibly circulate in the food room, gradually reducing the water content to achieve drying.The low-temperature and low-humidity air continuously absorbs the surface moisture of food in the forced circulation; the air that reaches the saturated state passes through the evaporator. Due to the evaporation of the refrigerant in the evaporator, the surface temperature of the evaporator drops below the dew point temperature of the air. After the air passes through the evaporator, it is cooled and the moisture is precipitated, and the precipitated moisture is discharged from the water collector. The reservoir body; the low-temperature and low-humidity air then enters the condenser, since the high-temperature gaseous refrigerant from the compressor flows in the condenser, the air is heated to form dry air; then it is mixed with the saturated air to generate low-temperature and low-humidity air for repeated circulation.Food that has been dried by a cold air dryer can not only maintain its original quality, but also be easier to pack, store, and transport.