The susceptibility tensor of saturated magnetized ferrite in frequency domain in laboratory coordinate system is gained by using the transfer matrix between the principal and the laboratory system, and then its form in Z-domain is derived by Z-transform (ZT). The ZT-finite-difference time domain method applied to the ferrite subject to an arbitrary direction of external dc magnetic field is obtained. The co-polarized and cross-polarized backward radar scattering cross-section for a saturated magnetized ferrite sphere are obtained by the presented algorithm. The computed results indicate the correctness and feasibility of the method.