Damage and fracture of Ni-Ti plate during high velocity impact have been investigated in this paper.The deformation microstructures have been studied by optical microscope.The results indicate that stress induced martensitic phase transformation (SIM) in Ni-Ti plate matrix for Austenite phase in the process of penetration.Defomation and fracture of Ni-Ti plate due to shearing band and micro-crack nucleated in interface with fracture mechanisms of microvoid nucleation, growth and coalescence.