Aiming at the fracture phenomenon of sheet metal in roll bending, for 6061-T6 aluminum alloy, a method to predict the fracture of roll bending parts was proposed, and the fracture mechanism was investigated. Then, the fracture behavior of 6061-T6 aluminum alloy V-shaped parts under two roll bending methods of fixed-length method and fixed-radius method was successfully simulated by finite element software Abaqus combined with damage model GTN, which was compared with the experimental results of roll bending. The results show that the GTN damage model is reliable to predict the fracture of 6061-T6 aluminum alloy sheets during roll bending. Microscopic morphology analysis and finite element mechanical analysis on the fractured areas of the roll bending parts reveal that the sheets are subjected to tensile and shear forces during roll bending. Furthermore, because the  maximum strain rate of sheets formed by the fixed-radius method increases faster than that by the fixed-length method in roll bending, the sheets formed by the fixed-length method can obtain a higher fracture limit compared to those formed by the fixed-radius method.