Abstract: Two types of improved Hopkinson bar were used to measure the stress on the impact and support ends of a cellular metal specimen.The experimental results and high-speed photography showed,as the impact velocity increased,the stress on the impact end increased,while the stress on the support end didn't change.The stress uniformity of two ends became worse when the impact velocity increased.Based on the experimental results we infer that under the shock mode,the stress on two ends is unrelated to the thickness of the specimen,but related to the density of the materials.In the high-strain-rate experiment of cellular metal,axial inertia (wave) effect will lead to stress non-uniformity.The results would be the coupling of axial inertia effect and strain rate effect and could not represent the dynamic mechanical properties of the materials.