Abstract: In order to study the dynamic response of 675 high strength armor steel after impact by projectile, it is necessary to determine a set of material model of 675 armor steel suiTab. for penetration simulation calculation. Therefore, the dynamic and static mechanical properties test and material fracture test of 675 armor steel were carried out, and the Johnson-cook constitutive model and failure model parameters of 675 armor steel were fitted according to the experimental results. At the same time, the penetration simulation model was established according to the ballistic test, and the numerical results were compared with the test results. The results show that: when the Johnson-cook constitutive model and failure model of 675 armor steel obtained from material performance experiment are applied to the numerical simulation, the average error between the simulation results and ballistic test results is 6.5%, and the maximum error is less than 10%. The parameters of Johnson-cook constitutive model and failure model are reliable, it is of great significance to the simulation of 675 armor steel under impact load.