A refrigerator cooling system , comprising: a refrigerant circulation flow path provided with a compressor , a condenser , a throttling device and an evaporator ; a defrosting branch ; and a switching device , wherein: the evaporator comprises a heat exchange core tube , the heat exchange core tube comprises a main inlet communicated with the throttling device and a main outlet communicated with the compressor , a middle section of the heat exchange core tube is provided with at least a middle inlets , a section of the refrigerant circulation flow path between an exhaust port of the compressor and the main inlet of the evaporator is a first flow path section , wherein both the condenser and the throttling device are located on the first flow path section , the defrosting branch is connected among the exhaust port of the compressor , the main inlet and the at least one middle inlets , the switching device is for switching the defrosting branch to communicate the exhaust port of the compressor with at least one of the followings: the main inlet and the at least one middle inlets , to enter a defrosting working mode, and the switching device is further for switching the first flow path section to be in a circulating state, to enter a cooling working mode. a refrigerant circulation flow path provided with a compressor , a condenser , a throttling device and an evaporator ; a defrosting branch ; and a switching device , wherein: the evaporator comprises a heat exchange core tube , the heat exchange core tube comprises a main inlet communicated with the throttling device and a main outlet communicated with the compressor , a middle section of the heat exchange core tube is provided with at least a middle inlets , a section of the refrigerant circulation flow path between an exhaust port of the compressor and the main inlet of the evaporator is a first flow path section , wherein both the condenser and the throttling device are located on the first flow path section , the defrosting branch is connected among the exhaust port of the compressor , the main inlet and the at least one middle inlets , the switching device is for switching the defrosting branch to communicate the exhaust port of the compressor with at least one of the followings: the main inlet and the at least one middle inlets , to enter a defrosting working mode, and the switching device is further for switching the first flow path section to be in a circulating state, to enter a cooling working mode. the evaporator comprises a heat exchange core tube , the heat exchange core tube comprises a main inlet communicated with the throttling device and a main outlet communicated with the compressor , a middle section of the heat exchange core tube is provided with at least a middle inlets , a section of the refrigerant circulation flow path between an exhaust port of the compressor and the main inlet of the evaporator is a first flow path section , wherein both the condenser and the throttling device are located on the first flow path section , the defrosting branch is connected among the exhaust port of the compressor , the main inlet and the at least one middle inlets , the switching device is for switching the defrosting branch to communicate the exhaust port of the compressor with at least one of the followings: the main inlet and the at least one middle inlets , to enter a defrosting working mode, and the switching device is further for switching the first flow path section to be in a circulating state, to enter a cooling working mode. <EOS>