The utility model discloses a U-shaped channel steel which is used for protecting a supporting beam of a hydrator. The U-shaped channel steel comprises a channel steel base material layer and a durable layer; the channel steel base material layer is provided with grooves on the external circumferential wall for containing the supporting beam; and the durable layer is arranged on the external surface of the channel steel base material layer. When in use, the U-shaped channel steel is arranged on the external wall of the supporting beam for protecting the supporting beam. According to the U-shaped channel steel disclosed by the utility model, the durable layer is arranged on the external surface, so that the durable performance of the U-shaped channel steel can be improved; and moreover, the service life is prolonged, the frequency in replacing is reduced, and the labor intensity of operators can be effectively reduced.