Abstract: An automatic positioning device for helical tomotherapy plan verification is provided. The device includes a base located on a treatment bed of helical tomotherapy equipment, a lifting platform fixedly connected to a top of the base, a three-dimensional verification phantom fixedly connected to other ends of the two support rods, and an early warning component. A bearing platform is fixedly connected to a top of the lifting platform, a moving platform is arranged on the bearing platform, and ends of two support rods are fixedly connected to a side, close to the treatment bed, of the moving platform. The three-dimensional verification phantom extends into a treatment aperture through the moving platform. The early warning component includes two early warning pieces respectively arranged on the two support rods.