The present invention discloses a modular sheet-tube type indirect evaporative cooling air conditioning unit comprising a unit housing, two opposite side walls of the unit housing are respectively provided with a primary air intake and an air outlet, and an air filter, a modular sheet-tube type indirect evaporative cooling device and an air blower are successively disposed in the unit housing in the air flow direction after the air enters the unit housing; and a secondary air exit is disposed at a top wall, over the modular sheet-tube type indirect evaporative cooling device, of the unit housing. The modular sheet-tube type indirect evaporative cooling air conditioning unit has the advantages that the heat exchange effect is good and usage is flexible, and air conditioning can be implemented by individually using indirect evaporative cooling.