Abstract: Based on a twin-characteristic-parameter method and stress wave theory, dynamic buckling displacements of rectangular thin plates subjected to axial in-plane impact are obtained analytically by solving nonlinear equations for the dynamic balance with a supplementary restraint-equation at the compression-wave front. In the dynamic buckling process of the rectangular thin plate, the relations of its thickness-width rate, the amplitude of impulsive loads, buckling modes and critical buckling length are found out. The buckling modes obtained agree well with those obtained by difference methods in former literatures.