Abstract: Ti6Al4V alloy samples were symmetrically and asymmetrically impacted by using a one-stage light gas gun. The recovered samples were analyzed by the scanning electron microscopy and X-ray diffraction. Results indicate that with the increasing of the impact speeds,the samples are distorted to different degrees. Meanwhile,the microcracks induced by the shock wave cause the material damage and the material damage accelerates the production and extension of the microcracks. Furthermore,the X-ray diffraction analysis shows that the impact can improve the crystallization of the material and there forms a metastable structure during the cooling process that can advances to some extent the impact toughness.