Abstract: This paper deals with the inverse Problem to recovery the shape of a three-dimensional obstacle from the knowledge of the far-field pattern of the scattering wave. A simple fast method is proposed for solving the inverse problem, which is based on a weighted superposition technique of the far-field data at a finite number of observation directions. The method requires no a prior knowledge of the type of boUndary condition imposed on the objects, nor does it depend upon prior information about the nUmber of the objects. Some numerical examples are given with the fleded aperture far-field data showing Validity and practicality of this method for low wavenumbers.