The invention discloses a tension clamp, which comprises a tension clamp housing, a drainage plate, and a drainage clamp. The drainage plate is fixed on a main pipe, the drainage clamp and the drainage plate are connected by bolts, and a wedge-shaped groove is arranged on the drainage plate. , the wedge-shaped plate on the drainage clamp is sleeved in it, the tension clamp housing includes a main pipe and a steel anchor, the main pipe is a hollow structure, one end of the main pipe is fixedly connected with a steel anchor, and the other end of the main pipe is provided with a second A lined aluminum pipe, a second lined aluminum pipe, and reinforced steel pipe. The main tube of the hollow structure is equipped with the first lined aluminum tube, the second lined aluminum tube, and the reinforced steel tube to ensure the strength of the main tube and make it better adapt to harsh service conditions. The drainage plate is designed with wedge-shaped grooves. Used in conjunction with the wedge-shaped drainage clip, when the drainage clip moves down, the wedge-shaped structure makes the cooperation between the drainage plate and the drainage clip tighter and tighter, even when the fixing bolts are loose, the C-shaped groove makes it difficult for the drainage plate to come off.