Cellular materials have attracted much attention in the applications in energy absorption,heat exchange and light weight load-bearing,due to their excellent properties combining light weight,outstanding mechanical behavior and low thermal conductivity [1,2].With the rapid development of additive manufacturing technology,periodic micro-lattice structures have attracted much attention due to their better properties than stochastic foams.Titanium and its alloys,which have higher specific strengths,modulus and melting temperatures than aluminum and steel,exhibit a promising prospect in applying as the matrix of cellular materials [3].In this paper,Electron beam melting(EBM)method is adopted to fabricate the Ti-6Al-4V micro-lattice structure(Fig.1).Dynamic experiments are performed to investigate the mechanical properties of the specimens by SHPB apparatus.In order to reveal the effect of surface imperfection on the dynamic properties,finite element model considering the surface quality of struts(Fig.2)is built and numerical simulation is conducted to exhibit the stress distribution and deformation evolution of the lattice structures under different impact speeds.