The invention discloses a multifunctional high-precision constant-temperature and constant-humidity control freezing and refrigerating system. The system is formed by a refrigerating system, a refrigeration house body, an air supply and return system and a control system. By means of the refrigerating system, adjustment of the evaporating temperature ranging from -40 DEG C to 0 DEG C can be achieved, and the refrigerating system is composed of a scroll compressor, a gas-liquid separator, an ice temperature evaporator, a thermostatic expansion valve, an electromagnetic valve, a quick-freezing evaporator, an electronic expansion valve, an interstage cooler, a liquid storage device, a hot gas bypass valve, a dry filter, a liquid viewing lens, an air-cooled condenser and an oil separator; and the air supply and return system is arranged in the refrigeration house body, and comprises a quick-freezing air supply and return system, an ice temperature supply and return system and a hot gas circulation defrosting system. According to the system, corresponding food processing can be carried out according to different requirements, the refrigeration house using rate is greatly improved, and economic benefits are considerable; and intelligent volume variable adjustment of the refrigerating system can also be achieved, and therefore the constant-temperature, constant-humidity and constant-air-speed function meeting the different food processing requirements is achieved.