Disclosed is a refrigerating system for a motor vehicle with a middle or rear engine. The refrigerating system comprises an air conditioner compressor, at least one evaporator, at least one condenser, a heat exchanger and a control unit. The air conditioner compressor is driven by the middle or rear engine to be used for conveying a refrigerant, the evaporator is used for evaporating the refrigerant so as to refrigerating a front portion of a passenger compartment, the condenser is used for condensing the refrigerant, the heat exchanger is used for refrigerating the refrigerant flowing to the evaporator through the refrigerating quantity of the refrigerant from the evaporator, and the control unit is used for limiting the temperature of the refrigerant entering the air conditioner compressor. When the refrigerant enters the compressor, due to the fact that the temperature of the refrigerant is limited, the temperature which causes damage to the compressor can be avoided; meanwhile, the situation that the refrigerant is heated along an overlong flowing path arranged in the engine and from a rear portion area of the motor vehicle to the compressor is taken into account, and therefore the refrigerating system which is used in the motor vehicle and has the long service life can be obtained.