Cable supporting device

The invention relates to the technical field of power transmission line facilities, and particularly discloses a cable supporting device. A U-shaped notch, a portal frame and a fixed pulley are arranged at the top of a supporting rod, a pull rope wound on the fixed pulley is connected with a hook, a cable is pulled into the air through the pull rope, the portal frame is jacked up after the cable touches the top of the portal frame, the cable slides into the U-shaped notch, at the moment, the portal frame is fixed through a fixing rope connected with the portal frame, and a space is formed by the U-shaped notch and the portal frame. The cable is positioned in the space, so that the cable can be tightened; a movable straight cylinder and an air cylinder are further arranged, meanwhile, a second vertical rod of the portal frame is arranged to be hinged to the transverse rod, the supporting rod can be assisted to be in an upright state, and after wire tightening is completed, the cable drives the portal frame to