The invention discloses a single-rod folding ladder, which mainly comprises a main rod and horizontal rods, wherein the main rod is provided with a hinge element; the horizontal rods are hinged with the main rod through the hinge element; a ladder butt is arranged at the lower end of the main rod; the horizontal rods are distributed at two sides of the main rod; the hinge element is composed of a hinge shaft and a hinge pressure sheet; a groove is arranged on the hinge shaft; the main rod is an I-shaped structure; and a supporting pendant is arranged on the ladder butt. The main rod disclosed by the invention is an I-shaped vertical rod; the horizontal rods are alternatively arranged at the two sides of the main rod; the horizontal rods can be folded upwards and embedded inside the I-shaped main rod; and the horizontal rods are supported on the main rod by utilizing bumps below one end of the main rod when being opened so as to play supporting and balancing roles, so that the horizontal rods can be located in a horizontal state. The single-rod folding ladder disclosed by the invention is small in volume after being folded, less in material, light in weight and convenient for carrying and is suitable for various climbing operations.