The utility model relates to a double-layered copper-brazed steel tube machine, which comprises a decoiler, a tube machine head, a blazing furnace, traction equipment, an eddy current flaw detector, a marking device and a lap machine. A vertical straightening device is added at the front of the eddy current flaw detector. A horizontal straightening device and secondary traction equipment are added at the back of the eddy current flaw detector. During the operation of the double-layered copper-blazed steel tube, a plurality of fulcrums are formed under the effect of five straightening wheels arranged in top and twin-side shape in the vertical direction of the vertical straightening device and under the effect of five straightening wheels arranged in top and twin-side shape in the horizontal direction of the horizontal straightening device. Moreover, the steel tube is tensioned under the tension of the secondary traction device and the quality flaw is detected by the eddy current flaw detector. When the marking device works, the double-layered copper-brazed steel tube does not shake, so the eddy current flaw detector is not interfered and the detection can be carried normally.