Defrosting control system and control method of refrigerator

The invention relates to a defrosting control system and a defrosting control method of a refrigerator. The system comprises a controller, a circulating fan, and a defrosting temperature sensor, a refrigerating chamber temperature sensor, a freezing chamber temperature sensor and an environmental temperature sensor connected with the controller, wherein the circulating fan is arranged beside a refrigerator evaporator; an air flue where the circulating fan is positioned is provided with a freezing chamber air inlet and a refrigerating chamber air inlet, and the air inlets are provided with a freezing chamber air inlet electric air door and a refrigerating chamber air inlet electric air door respectively; the air flue where the other side of the refrigerator evaporator corresponding to the circulating fan is positioned is provided with a freezing chamber return air port and a refrigerating chamber return air port; and the freezing chamber return air port is provided with a freezing chamber return air port electric air door. Refrigeration and defrosting are controlled by controlling the electric air doors of each air port and the circulating fan so as to save electrical energy, avoid generating continuous high temperature to affect the temperature of the refrigerator and reduce the energy consumption; and the refrigerator evaporator is defrosted through relative hot air of the refrigerating chamber by using the temperature difference between the refrigerating chamber and the refrigerator evaporator, so the energy utilization rate is high and the energy consumption is saved.