The invention relates to a reverse-flow solution desiccant fresh air handling unit driven by a heat pump. The fresh air handling unit comprises a first gas-liquid contact exchange module, and a second gas-liquid contact exchange module, wherein a solution outlet of the first gas-liquid contact exchange module is communicated with a spray device of the second gas-liquid contact exchange module through a first pipeline; a solution outlet of the second gas-liquid contact exchange module is communicated with a spray device of the first gas-liquid contact exchange module through a second pipeline; a heat pump circulation pipeline is successively connected with a first end of a compressor, a condenser, an expansion valve, an evaporator and a second ends of the compressor to form circulation; and the first pipeline performs heat exchange through the condenser, and the second pipeline performs heat exchange through the evaporator. According to the reverse-flow solution desiccant fresh air handling unit, the evaporator is used for cooling a strong solution output from an outlet of a regeneration module, and the condenser is used for heating a dilute solution output from an outlet of a dehumidification module, thus effectively using energy of heat recovery between the dehumidification module and the regeneration module, and optimizing the system efficiency.