The invention discloses a big supercooling degree machine room air conditioner. A condenser consists of two parallel condenser tubes; and a supercooler is positioned between the two parallel condenser tubes of the condenser. The refrigeration cycle comprises that: a refrigerant is converted into high-temperature high-pressure gas by the compressor, enters the two parallel condenser tubes of the condenser to exchange heat with air and enters a high-pressure liquid reservoir; the refrigerant flowing out of the high-pressure liquid reservoir enters a supercooler for supercooling heat exchange and becomes the refrigerant with a big supercooling degree; the refrigerant with the big supercooling degree is throttled by an expanding valve and enters an evaporator for heat exchange; and finally the refrigerant is returned to the compressor to complete the whole refrigeration cycle. Because the refrigerant is supercooled after the high-pressure liquid reservoir, the problem that the supercooling degree is lowered because the conventional refrigerant is supercooled and then enters the high-pressure liquid reservoir is effectively solved; and because of the big supercooling degree, the refrigerant does not bubble when passing the expanding valve, the operating stability and reliability of the expanding valve are improved, and the refrigerating capacity and the refrigerating energy efficiency of the system are also improved.