The utility model relates to a horizontal over-current sliding seat comprising a body, a semicircular groove body, a groove body, a locking lead screw, an arc-extinction rope, an arc-extinction pulley, and a locking ring. The whole body is in an L shape; and a mounting lifting ring and a screw hole are arranged at the body. The locking ring is connected to one end of the locking lead screw; and the other end of the locking lead screw passes through the screw hole and then is connected with the groove body. One end of the body is connected with the semicircular groove body. The groove body, the body and the semicircular groove body form a lead clamp groove. A U-shaped notch is formed at the lower portion of the groove body; the arc-extinction pulley is installed at the U-shaped notch; and the arc-extinction rope winds around the arc-extinction pulley. According to the scheme, the arc-extinction rope, the arc-extinction pulley, the lead and the current leading unit are located at the same plane after installation, so that no clamping phenomenon occurs when the arc-extinction rope makes motion and thus the personal and equipment security is ensured to the greatest extent. The locking lead screw is parallel to the ground and thus the locking lead screw and the locking ring face the tower body directly, so that the worker can install the sliding seat conveniently to the greatest extent and thus the physical output of the human body can be effectively reduced.