Abstract: When the analyzed cylinders are rather complex, the FDTD method is very suitable to analyze this kind of scattering problems. But usually the iterative time of FDTD method is quite long, the iterative calculation of FDTD method is needed to perform at many angles in this case. Besides, it is necessary to perform a large number of near-far field transformation when the wide band RCS is computed. In this article, the multivariate Pade interpolation technique is employed to obtain wide-angle and wide-band results with satisfactory accuracy. By use of RCS results, which are obtained using FDTD method, the two-variable rational function of RCS pattern can be achieved. Then the wide-angle and wide-band RCS pattern can be calculated by use of the rational function. The least square method is adopted to make full use of the RCS results from FDTD method as possible.