The invention relates to a multi-condenser and double-return-air bypass dehumidification 
fresh air unit and an 
air conditioning method. The multi-condenser and double-return-air bypass dehumidification 
fresh air unit comprises an air feed channel and an exhaust channel. A first 
heat exchanger and an air feeder are sequentially arranged at the position of the air feed channel. A second 
heat exchanger and an exhaust fan are sequentially arranged at the position of the exhaust channel. The second 
heat exchanger is connected with an auxiliary heat exchanger. A first return air 
bypass valve and a second return air 
bypass valve are arranged between the air feed channel and the exhaust channel. According to the multi-condenser and double-return-air bypass dehumidification 
fresh air unit, during refrigerating, the second heat exchanger serves as a condenser, a 
refrigerant is condensed through the indoor low-temperature exhaust air, the 
condensation temperature of the unit is reduced, and reheating is conducted through mixing of bypass return air and low-temperature fed air on the air feed side so that 
cooling capacity losses caused by cold and heat offset can be avoided; in a heating inner circulation mode, an outdoor unit can be started to rapidly increase the indoor environment temperature; and in an outer circulation mode, the second heat exchanger serves as an 
evaporator, the 
refrigerant is made to be evaporated through the heat of indoor exhaust air, the 
evaporation pressure and the heating capacity of the unit are increased, the 
power consumption of the unit is reduced, and the frosting risk of the unit is avoided.