Abstract: Nanocrystalline Ni bulk was prepared by high-energy ball milling and hot-pressure sintering.The dynamic impact properties were tested at different high strain rates by using Hopkinson bar.The results indicate that the nanocrystalline Ni bulk had higher strength,up to 565 MPa.The impact strength increased with the increase of strain rate.However,the strain hardening behavior of the samples was not obvious and showed smooth plastic flow behavior.Based on the experimental results,the predicted deformation mechanism of the nanocrystalline Ni was the combination of dislocation gliding and grain boundary sliding.