Abstract: In this paper, a new technique on analyzing the scattering characteristic of complex objects on the ground using FDTD method is presented. In order to deal with the electromagnetic interaction of the ground and the object, scattering field of the ground is calculated firstly, the incident field and the scattering field of the ground are treated as two inducing sources to the object, which is accurately modeled by the procedure proposed in this paper. And then, the scattering field of the object is calculated. Finally, the computing result of a truck with this method is given and compared with the experimental data.