Abstract:Quasi-static and dynamic mechanical properties of Ni-Ti shape memory alloy bar have been investigated by using electronic universal testing machine (INSTRON5985) and Split-Hopkinson Pressure Bar (SHPB), and analyze the microstructure under different condition through microscopic analysis methods such as XRD, OM and SEM. The experimental results show that Ni-Ti alloy original organizations consist of B2 austenitic phase, B19’ martensite phase , Ni3Ti4 phase and with small equiaxed grains; quasi-static and dynamic compression all occur stress induced martensite phase transformation, but dynamic compression stress-strain curve does not appear yield platform and presents strain rate hardening effect; within a certain range of strain rate, the striped organizations increase with the increase of strain rate, and the degree of stress induced martensite phase transformation increases.