Abstract: Based on Impedance Boundary Condition (IBC), a Method of Moments-Physical Optics (MoM-PO) hybrid method is proposed for modeling the electromagnetic scattering from three-dimensional (3-D) anisotropic impedance surface. The surface equivalence principle is adopted while the scattering can be replaced by the radiation of surface electromagnetic currents in the MoM-and the PO-region, with the current expanded by 3-D Rao-Wilton-Glisson (RWG) vector basis functions. The simulation of target coated with anisotropic material is performed with the electromagnetic parameters characterized by the surface impedance dyadic, while the numerical results agree well with the exact solutions such as Mie series, which shows the validity of the proposed method.