Abstract: A three-dimensional linearized elastodynamic inversion method to reconstruct the shape of the scatterer has been investigated in this paper.The volume type of integral representation is formulated for the scattered field.Then Born approximation is introduced to the far-field expression of scattering amplitudes in the integral representation.The shape reconstruction of the scatterer is performed by the inverse Fourier transform of the approximated scattering amplitudes.A numerical example is given for the reconstruction of spherical cavity in the rod by the Born inversion.