The present invention includes a chassis, of which the left upper end is provide with a seat body, the upper end of the seat body is provided with a mounting plate, the upper end of the mounting plateis provided with a badminton racket fixing assembly and a thread clamping assembly, the right upper end of the chassis is provided with a box body, the upper end of the box body is provided with a guide shaft, a sleeve is movably arranged on the guide shaft, the upper end of the sleeve is provided with a traction head, the right end of the traction head is connected with a hook, the hook is connected with an electronic scale, the two sides of the electronic scale are connected with a support frame through the connection shaft, and the left and right support frames are connected with a slider.The slider is arranged in the box body and moves back and forth through the electric actuator. The upper end of the box is provided with a distance adjusting member for defining the position of the traction head. The purpose of the invention is to provide a badminton racket threading device with adjustable bending tension, which has simple structure and convenient use, and can adjust the bendingtension of the net thread in the process of threading the badminton racket, so that the bending tension of the net thread reaches the optimum state, thereby exerting the excellent performance of the badminton racket.