For the 2D profile stretch bending of stretch bending machine that gives a bending moment to the profile, according to the principle of stretch bending, it is necessary to ensure that any point in the inner and outer arcs of product is in a stretched state. Therefore, for the existing stretch bending machine, the influence laws of different positions in the rotation center of stretch bending on the product state after stretch bending were studied. The research results show that the distance between the rotation center position and the final position of stretch bending must be less than 5 mm, otherwise some points of product may be in a compression state. The products produced by the stretch bending die designed according to experience are unqualified. After the die is repaired, the unilateral stretching amount of product is 11.60 mm, and the actual error with the theoretical value (12.18 mm) is 0.48 mm. At the same time, there is also a stretching amount in the straight line segment, so the stretching amount of the straight line segment should be considered as appropriate when designing the springback line. The forming state of product is predicted by simulation, and the actual and simulated dent error is 7.5% before die repairing and 8.3% after die repairing. Thus, the simulation can be added to verify the design of stretch bending die so as to avoid waste of resources caused by later die repairing.