Internal jacking anti-deformation device

The utility model discloses an inner jacking anti-deformation device which comprises a rectangular frame composed of four round pipes, and a plurality of sets of evenly-distributed nut fastening devices are arranged on the two round pipes on the upper side and the right side of the rectangular frame respectively. A plurality of groups of fastening sleeve devices which are uniformly distributed are arranged on the circular tube on the lower side of the rectangular frame; a nut fastening device arranged in the middle and a plurality of fastening sleeve devices symmetrically arranged at the two ends are arranged on a round pipe on the left side of the rectangular frame. The device is simple in structure and easy to operate, when a joint product with a square opening is spliced, the fastening sleeve device and the nut fastening device can be adjusted to abut against a side plate at a flange hole, it is guaranteed that when the product is welded, the phenomenon that the flange hole is heated to deform into a rhomb