The invention provides a device for improving the current carrying capacity of a cable. The device for improving the current carrying capacity of the cable comprises a conductor tube which is connected in parallel with the cable. A flowing channel used for accommodating a flowing fluid is arranged in the conductor tube to form a low temperature zone around the cable, wherein the temperature of thelow temperature zone is below the temperature of the cable. According to the device for improving the current carrying capacity of the cable, through the conductor tube connected in parallel with the cable, the resistance of the line where the cable is located is reduced; current flowing on the cable is reduced; the loss of the current carrying capacity of the cable is reduced; the current carrying capacity of the cable is improved; the flowing channel used for accommodating the flowing fluid is arranged in the conductor tube to reduce the temperature of the conductor tube and form the low temperature zone around the cable, wherein the temperature of the low temperature zone is below the temperature of the cable; more heat generated by the cable is absorbed to improve the heat dissipation potential of the cable; the loss of the current carrying capacity of the cable is further reduced; and the current carrying capacity of the cable is improved.