Abstract: A dehumidifier with a pre-cooling device includes a compressor, a condenser, an expansion device, a microchannel pre-cooler and an evaporator assembly. During operation, moist air enters from an air inlet of the dehumidifier, and passes through the microchannel pre-cooler to make the moist air to reach a saturated steam state and passes through the evaporator assembly for heat exchange to condense and dehumidify the moist air, and the dehumidified air passes through the condenser for heating and finally discharged from the air outlet, so that the water vapor in the moist air can be condensed into a liquid better to improve the condensation and dehumidification effects of the evaporator and reduce the air humidity effectively, so as to improve the dehumidification effect of the equipment.