The invention discloses a clamping tool for fitter processing, which discloses a support area for the inner wall of the pipe fitting through multiple sets of support ribs, so as to build an effective high-strength internal support structure to ensure that the pipe fitting will not be affected by the external clamping force. The device that is too large to cause deformation is characterized in that the fixed frame is a rectangular frame structure, the two ends of the fixed frame are arched to form arc blocks, and a set of guide grooves are respectively opened at both ends of the fixed frame, at least two A sliding column is placed in a group of guide grooves, and the two ends of the sliding column are respectively fixedly connected with the two sides of the fixed frame, and the two ends of the fixed frame are respectively provided with avoidance grooves, and the wedge-shaped top block is placed in the fixed frame , two sets of supporting ribs are respectively placed on both sides of the wedge-shaped top block, and a chute is opened on the supporting ribs, and the chute corresponds to the sliding post, and one set of supporting ribs is correspondingly inserted in a In the group guide groove, the sliding column is inserted in the chute.