Abstract: Based on Maxwell's equations, an analytical formulation is derived for the equivalent currents on conducting objects coated with chiral material illuminated by a plane wave. By using the tangential plane approximation, the physical optics (PO) solutions are obtained. The backscattering of the T type structure and the cone cylinder geometry are computed with this method, the effect of different chiral parameters is discussed, and some useful conclusions are given. This work provides an efficient approach for fast prediction of the scattering by the electrical large conducting objects coated with chiral material.