The invention discloses a bird nesting prevention device for a power transmission tower, which is mounted on the tower and comprises two steel plates. The two steel plates are connected by hinges; besides one edges connected by the hinges, each edge of the two steel plates is provided with round holes; the two steel plates are randomly unfolded in a range of 180 degrees; the two steel plates are fixed on the tower by connecting pieces; the connecting pieces pass through the round holes. The bird nesting prevention device disclosed by the invention is simple in structure, convenient to install, low in cost and long in service life, and can effectively make up the defect of poor bird driving effect when bird feces proofing splinters are positioned above phase insulator strings in a cat-head type tower and a cup type tower.