The welding arc shape shall be processed by milling machine during the tube welding, which is difficult to meet mass production requirement. Through the hanging tube part forming process analysis, the punching incision forming process was adopted. The process is simple with low cost, high efficiency and good quality advantages. Two sets of incision cutting die were designed and the punch and die cutting graphics and size were provided. The tube wall deformation was briefly analyzed. Through years of practice, it is proved that the technology and die application condition is quite good with stable production rate.