From three aspects of adjusting the first drawing fillet, adding process convex and process cut fillet, the changing law of forming quality for rear mounting plate of engine bracket was studied by finite element analysis software Autoform, and the influence laws of the ratio of the first drawing fillet r0 and the secondary drawing fillet r1 on the defects and material thicknesses were analyzed. Then, with the increasing of the first drawing fillet r0, the material thickness of final formed workpiece first increased and then decreased, and the closer to r0 = 0.75r1 (i.e. k=0.75)is, the thicker the material is. The results show that when r0=r1, adding process convex can improve the fracture defect to a certain extent, and when r0=0.75r1, adding process convex has little effect on improving defects and material thickness. Furthermore, with the increasing of process cut fillet r切口, the stress concentration factor is effectively reduced, the point corresponding to the original fracture position in FLD completely enters the safe area and gets farther and farther from the forming limit curve, the material thickness shows an increasing trend, and the defect improvement effect is obvious.