In the present work, the structure optimum design and simulation analysis of automobile side-door impact beam was carried out by using Finite Element (FE) method. The model of the side-door impact beam impacting with the rigid pole was set up according to the requirement of the Federal Motor Vehicle Safety Standards intensity test of side door (FMVSS214). The numerical simulations were carried out using the software LS-DYNA. Attention was focused upon finding an optimum cross- section shape of the beam in order to improve the energy absorption character. Several types of impact beams were studied and compared. Results show that the energy absorption characters of the beam improved obviously when square cross section with the wall slope 10° and a 9 mm long curled edge was adopted.