Abstract: The experimental investigation of TiNi cantilever with circular cross-section under transversal impact loading was conducted by using a revised Hopkinson bar apparatus, and compared to 45 steel cantilever. The purpose of this study is to explore the effect of phase transformation on the dynamic behavior of structures. The results show that at the same impact condition, the energy absorbing efficiency of a TiNi cantilever is better than that of a 45 steel cantilever. It is found that a local transformation hinge (TH) may generate at the inner side of TiNi cantilevers fixed end during impact loading, which changes the resistance characteristic of the cantilever. The TH disappears after unloading and the TiNi cantilever recovers to its original position, however, the 45 steel cantilever has large residual deformation. The impact response of TiNi cantilever is controlled by the thermo-elastic martensite phase transformation and inverse transformation, which differs from the conventional elastic-plastic mechanism.