Abstract: CNC incremental forming technology was used in the hole-flanging process,and forming force and thickness distribution during the forming process were studied.Effects of parameters such as forming tool diameter,vertical step size and the final hole diameter on the of hole-flanging process were analyzed.The results show that the usual limit flanging coefficient can not be used in CNC incremental forming of hole-flanging process to show the forming limit of the sheet blank.The forming force decreased quickly in the final stage of hole-flanging process.Compared with the fracture part,thickness distribution of the sucessful flanging one is more homogeneous.Pre-cut hole diameter of the sucessful flanging parts decreases with the increase of the forming tool diameter and vertical step size.When the diameter ratio of the final part and forming tool is less than or equal to 2.5,the part fractures at the hole edge because prolongation of the material has increased to limit.When other parameters are certain,initial effective forming distance will not increase with the increase of the final part diameter after reaching a certain value.