Die forging process of piston tail and its key technology are analyzed in detail. The key issue is to reduce friction force between punch and billet to facilitate metal flow towards two ends. Three-step forging scheme is used, namely preforming, final forging and cutting the flash. Preforming is critical for the success of the whole process and two schemes are compared. First two steps are simulated using 3D-Deform software. Simulation results show that the process is feasible and its validity is verified.