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Variable curvature 2-section of 2099 Al-Li alloy is important truss of Chinese independently developed large airplane C919, four roll bending forming is main method to manufacture this kind of part. Due to the high specific strength of Al-Li alloy and asymmetric structure of 2-section, compared to section of conventional aluminum alloy, 2-section of Al-Li alloy was extremely prone to oblique bending. Therefore, four roll bending process of 2-section was simulated by finite element software ABAQUS, effect of roller gap, clearance between bottom roller and profile in vertical direction, displacement in X direction of left and right rollers was researched on oblique bending during four roll bending of 2-section, best roll bending process parameters was confirmed. Roll bending process experiment was carried based on it. The results show that 0.2 mm for roller gap, 0.3 mm for clearance between bottom roller and profile in vertical direction, 1.5 mm for displacement in X direction of left and right rollers can effectively solve the problem of oblique bending for roll bending of 2-section.