The invention discloses an air cooled refrigerator defrosting and humidifying device and a control method thereof, and relates to the technical field of refrigerators. The air cooled refrigerator defrosting and humidifying device comprises a refrigerator body, a refrigerating chamber, a freezing chamber, a refrigerating system, an air circulating system and a defrosting and humidifying system; therefrigerating system comprises a compressor, an evaporator, a capillary tube, a filter and a condenser; the compressor is mounted inside a compressor chamber below the refrigerating chamber; and theevaporator is communicated with the compressor, and is mounted inside an evaporator chamber on the rear side of the refrigerating chamber. The air cooled refrigerator defrosting and humidifying deviceprovided by the invention uses the principle that when solid frost on the evaporator is changed to be in a liquid state, heat is absorbed and the temperature is not changed; when defrosting is performed, the main control panel of the refrigerator controls a refrigerating blower to blow moist air produced by defrosting into the refrigerating chamber for moistening; by using a forced convection method, high humidity air is blown into the refrigerating chamber, the defrosting and heating time is shortened, so that when the system inside a single-system air cooled refrigerator enters into a defrosting period, the relative humidity average value is increased to 80 percent from 40 percent, and the fruit and vegetable fresh-keeping effect of the refrigerating chamber is improved greatly.