In this article, a method of establishing a scaled model for a full-size target composed both of medium and conductive material is proposed. First, the internal electromagnetic field of scale model equals the electromagnetic field of the corresponding full-size target is proved from the relation of size of target, and the operating frequency as the target and its scale model are illuminated by the identical incident electromagnetic wave. Second, a general expression of target scattering is given. Finally, the scattered field of scale model equal to the scattered field of the corresponding full-size target is demonstrated. All the measured results by the scaled model have a good agreement with the accurate solutions of the full-size target. Simulation shows that the effectiveness of the method used to the target of lossy medium is better than that of the principle of similitude. The method has the advantage of being free from the operating frequency, the target permittivity, and target permeability.