The invention discloses a cable thread tightening device. The device comprises a drill chuck, and the rear part of the drill chuck is provided with a drill chuck internal thread. A tractor is connected with the drill chuck, and the tractor includes a connecting shaft with an external thread. One end of the connecting shaft is equipped with an open traction head, and the traction head is provided with a loading hole in the middle. The connecting shaft is in threaded connection with the drill chuck internal thread through the external thread. The drill chuck is easy to open and close, the diameter of a cable clamped by the drill chuck can change between a few millimeters to tens of millimeters, the clamping force of the drill chuck is large, and a clamped cable is not easy to fall off.