The invention discloses an overhead line tightening device. The device comprises a main vertical rod, wherein a lighting lamp is arranged in the middle of the main vertical rod; an auxiliary vertical rod is arranged in the main vertical rod in a sleeving manner; the top end of the auxiliary vertical rod is in screw joint with a threaded sleeve arranged at the lower part of a main trunking rack; a group of extension trunking racks are arranged on each of the two sides of the main trunking rack; a top end vertical plate is arranged at the upper part of the main trunking rack; a top end platform is arranged at the top end of the top end vertical plate; extension rods are arranged on the two sides of the top end platform; a pull rod is arranged at the end part of each extension rod; a generator head is arranged at the upper part of the top end platform; the generator head is connected with a group of fan blades; the generator head is further electrically connected with a storage battery arranged on the top end vertical plate. The device has a lighting function, can be charged through wind energy, is energy-saving, environmental-friendly, high in strength and good in anti-wind capacity, can provide good protection and supporting effect on overhead power lines, and reduces the probability of disconnection of the power lines.