Numerical simulations of polarized scattering-3D imaging-profile reconstruction of a complex-shaped electric-large target above a rough surface are developed. The bidirectional analytic ray tracing (BART) method is first applied to calculation of polarized scattering from volumetric target and surface. By using the step-frequency (SF) radar working in downward-looking spotlight mode and moving within a two-dimensional circular arc aperture, a 3D matrix of backscattering fields in both the amplitude and phase is obtained. The three-dimensional fast Fourier transform (3D-FFT) algorithm is adopted for uniformly resampling data in <italic>X</italic> - <italic>Y</italic> - <italic>Z</italic> coordinate system, which are acquired by interpolating the collected uniformly sampling backscattering fields to quickly form a focused image. Automatic reconstruction of the target is well demonstrated. As validation and comparison, the scattering fields are also computed and compared using widely accepted software FEKO based on physical optics. The technique of imaging and reconstruction for a 3D complex-shaped perfect electric conductor (PEC) electric-large target, such as a tank-like object, is presented.