Adjustable lifting bracket

The invention discloses an adjustable lifting bracket which is mainly applied to the technical field of lifting. Two lifting arms are arranged in parallel along the horizontal direction and penetrate through a rectangular pipe; lifting lugs are respectively arranged and welded on the two lifting arms and the rectangular pipe; two diagonal members are respectively hinged with the two lifting arms and a multistage hydraulic cylinder on the top and at the bottom; the two diagonal members are hinged with each other; two round pipes are respectively inserted into another two round pipes to form two groups of round pipes; the two groups of round pipes are respectively hinged with the two lifting arms and the multistage hydraulic cylinder on the top and at the bottom; pin shafts are respectively connected between the two lifting arms and the rectangular pipe and between the two groups of round pipes; and bolt and nut fasteners are respectively hinged among the lifting arms, the diagonal members, the round pipes and the multistage hydraulic cylinder. The lengths of the lifting arms, the section height, namely moment of inertia of cross-section and the positions of the lifting lugs are adjustable, the lifting bracket can adapt to different lifting distances and the gravity center position of a lifted structure, and the lifting bracket still has enough carrying capacity under the condition that the lifting arms are lengthened.