The present invention relates to an air conditioning system of a low-temperature type vinyl house used for a mushroom grower and the like by keeping air at a predetermined temperature and humidity, circulating the inside air evenly, and ventilating the air inside the plastic house through the filtered outside air A first cold / hot air purifier installed at any one of four corners of a first greenhouse for supplying cold air and hot air and supplying hot air through a double heater A second cold / hot air purifier installed at another corner of the first greenhouse located on a diagonal line of the first cold / hot air conditioner, for supplying cold air and hot air and supplying hot air through a double heater A first cooler installed at a first corner located at a far distance from the first cooler and a second cooler located at the other corner of the first greenhouse, A second cooler installed at the last corner of the four corners of the first greenhouse and supplying cool air A first outdoor unit connected to the first cold air conditioner and the first cold air conditioner and configured at a place outside the second vinyl house A second outdoor unit connected to the second cold / hot air conditioner and the second air conditioner and configured at another place outside the second greenhouse The air inlet formed with the first opening / closing valve is located above the ground surface of the corner where the first cool air blower is installed, passes under the inner bottom of the first vinyl house in a staggered manner and is connected to the upper part of the ground of the corner where the first cold / A first air circulation tube which surrounds the refrigerant pipe formed in the outdoor unit and surrounds the air refrigerant pipe in a spiral shape and in which an air discharge port is positioned in front of the blowing port of the first cold / hot air conditioner A first compressor connected to the first air circulation pipe leading from the bottom of the
