This paper deals with the local buckling characteristics and the energy absorption of the expansion tubes with the various dimensions of tubes and punch shapes. The local buckling load and absorbed energy during the tube flaring process were discussed for each cases of tube and punch shapes by finite element analysis. Absorbed energy of expansion tube is affected by the diameter and the wall thickness of tubes. Punch angle and expansion ratio also affect to the energy absorption. According to the buckling analysis, local buckling can occurs in some cases. The absorbed energy of expansion tube significantly decreases when local buckling occurs. For enhancement of energy absorption, it is important to predict local buckling load accurately. In this study local buckling load is predicted by modification of Plantema equation.