The impact-echo method has been applied to nondestructive evaluation for concrete structures. Taking out resonant frequencies responsible for the locations of reflectors in the frequency spectra, identification of reflectors is performed. Stack imaging of spectral amplitudes based on impact-echo (SIBIE) is developed, in order to improve the impact-echo and visually identify the locations of reflectors. In the present paper, two-dimensional dynamic BEM analysis is performed to confirm an applicability of SIBIE. At the peak frequencies in the spectra, distributions of the stress and deformation are clarified.