A transportation refrigeration system and a CAN ID allocation method for a transportation refrigeration system. The transportation refrigeration system includes: a refrigeration circuit including a compressor, a condenser, and a plurality of evaporators connected in parallel, all of which are connected to form a loop; a plurality of chambers, each of the evaporators being located in one of the chambers to adjust the chamber; a plurality of sensors of the same type, each of the sensors being installed in one of the chambers respectively; and a control unit, after being installed in place and energized, the plurality of sensors send their own identification codes to the control unit, and the control unit allocates a CAN ID to each of the sensors after receiving the identification codes of the sensors, so that the identification code of each sensor is bound to the corresponding CAN ID respectively.