Reconstructions of the 3-D model of buildings from single high-resolution SAR (Synthetic Aperture Radar) image were studied. After a detailed analysis on the electromagnetic backscattering model of buildings, the methods on how to calculate the backscattering coefficient of different reflectivity areas and on how to create a simulated SAR image from the CAD model of a building was proposed. The outlines and orientations of buildings were extracted using the double-bounce structures. The building height was estimated based on the iterative simulation and matching. The simulated SAR images are divided into different kinds of scattering areas. The Kullback-Leibler divergence between these areas was treated as a measurement of the matching degree. The tested height, at which the simulation SAR image obtains the best matching degree, is taken as the final estimated height. The above methods were evaluated on two real high-resolution SAR images. The reconstruction results are satisfying and prove the feasibility of 3-D reconstruction of building from single high resolution SAR image and the validity of the proposed approach.