The utility model discloses a vapour and liquid separator and have its refrigerating cycle device, refrigerating system. Vapour and liquid separator includes: barrel, low -pressure admission pipe, low pressure outlet duct and be suitable for the high -pressure pipeline of circulation refrigerant prescribe a limit to a separated space in the barrel. The one end of low -pressure admission pipe stretches into in order to emit into the refrigerant of treating gas -liquid separation in the separated space. The low pressure outlet duct stretches into in the separated space with the gaseous state refrigerant in the discharge separated space, and being located of low pressure outlet duct is equipped with the oil return opening in the part of separated space lower part. The high -voltage tube way has the heat transfer pipeline part that lies in separated space and carry out the heat transfer with the refrigerant with separated space, and the high -voltage tube way has the first exit and the second that stretch out the barrel to be imported and exported, and heat transfer pipeline part has spiral pipe portion. According to the utility model discloses a vapour and liquid separator has played subcooler, regenerator and gas -liquid separation's effect simultaneously.