The invention relates to the technical field of air conditioner heat pumps, in particular to a triaxial pressure high-efficient air cooled heat pump unit applicable to large temperature difference. The triaxial pressure high-efficient air cooled heat pump unit comprises a main path compressor, a main path oil separator, a four-way reversing valve, an outdoor heat exchanger, an outdoor draught fan, a first one-way valve, a second one-way valve, a third one-way valve, a fourth one-way valve, a fifth one-way valve, a sixth one-way valve, a subcooler, a drying filter, an observation mirror, a first expansion valve, a medium-pressure gas-liquid separator, a second expansion valve, an indoor heat exchanger, a low-pressure gas-liquid separator, an evaporation pressure adjustor, an auxiliary path compressor, an auxiliary path oil separator and a connecting pipe. The triaxial pressure high-efficient air cooled heat pump unit solves the prominent problems about the high-temperature refrigeration working mode at summer and the low-temperature heating working mode at winter, has the characteristics of being wider in energy adjusting range and rapid and energy-saving in defrosting, and widens the application field of the air cooled heat pump.