The embodiment of the utility model discloses CO2 laser is clear away transmission line and is floated attached cooling system of string thing device, include: water -cooling piece, water pump, pipeline and heat exchanger, the heat exchanger passes through the pipeline and the water pump is connected, the water pump passes through the pipeline and the water -cooling piece is connected, the water -cooling piece passes through the pipeline and the heat exchanger is connected. The embodiment of the utility model provides a drive transmission line through the water -cooling piece to CO2 laser and float the module absorption heat of hanging in the thing device that generates heat, recycle the heat that the water pump makes the coolant liquid circulation in the pipeline and takes away the water -cooling piece, the absorptive heat of coolant liquid through the heat exchanger arrange CO2 laser clear away transmission line float hang the thing device outside, can make CO2 laser clear away transmission line floats and hangs the module of generating heat in the thing device and cool down, extension CO2 laser is clear away transmission line and is floated a string thing device working life, it clears away transmission line and floats the useful output of stabilizing of hanging the thing device and having the continuation to guarantee CO2 laser.