The utility model discloses a supporting frame which is provided with a supporting frame body, wherein the upper part of the supporting frame body is of a semicircular-arc structure matched with a rolled tube. The supporting frame body is of a frame-shaped steel structure formed by connecting a bottom plate, a longitudinal rib plate, a reinforcing rib plate, a side blanking plate, a top panel and a top semicircular panel. The supporting frame can be used for assisting a lifting-up system in finishing a lifting-up operation for a jacket rolled tube, and thus, the other lifting way is provided for the jacket rolled tube; the increased length and weight of a large rolled steel tube in a workshop are increased, and the lengthening operation for the large rolled tube in the workshop is realized; the welding quality for the large lengthened rolled steel tube is improved, the work efficiency for lengthening the large rolled steel tube is increased, and the safety for lifting the large rolled tube is improved; and the utilization ratio of a shop traveler in the workshop is reduced, and the building cost of the rolled tube is reduced.