It cannot be processed in the existing holeflanging process when the flanging hole and tube have the same diameter. Therefore, a new process is proposed. Taking the deformation characteristics of new process, the workhardening ability and the thickness change in the deformation zone into consideration, this paper presents a calculative method for tube flanging force. The simulation data in Abaqus show that the flanging force in this paper is more accurate than the sheet flanging force formula.