A new approach of imaging reconstruction of concealed targets from multi-angular scattering is presented. As the broadband stepped-frequency radar transmits planar wave from different azimuthal directions around the target, the backscattered electrical fields in both the amplitude and phase are obtained. The two-dimensional (2D) fast Fourier transform (FFT) algorithm for spline interpolation is adopted for uniformly sampled back scattering fields. Then, 2D images of a dielectric box with and without the concealed targets can be numerically simulated. The concealed targets can be well identified from the imaging reconstruction.