Abstract: By use of finite element method of explicit dynamics, the dynamic post-buckling of elastic perfect bars subjected to axial high-velocity impact is investigated. The initial dynamic buckling with a small amplitude parameter, given by the twin-characteristic-parameter solution, is employed as the initial condition of the nonlinear dynamic solution. Results obtained in the present study agree well with the experimental data in the reference. The present investigation reveals the mechanism of growth and spread of buckling deformation in the bar and the interaction between the axial stress wave and the buckling deformation during their impacting.