Radar cross section (RCS) is one of the most important characteristics describing an object from the point of view of radar detection capability. Therefore, accurate and fast calculation of RCS plays an important role in the process of designing and manufacturing military equipment. Radar cross section calculation for structures with complex surfaces or coatings, compared to simple PEC objects has become an important area of research in recent years. For example, PEC structures coated with absorbing layers and cloaks are very important in the design of stealth missiles and aircrafts. In this case, using the impedance boundary condition, the analysis of scattering problems is much easier because the electric and magnetic fields on the surface of the body are related to each other and there is no need to discretize and calculate the fields within the volume of the body. In, the purpose of this dissertation is calculating the RCS of different bodys of revolution (BORs) including PEC, structures modeled as single impedance or multi-impedance surfaces. For this purpose, first the integral equations EFIE, MFIE, CFIE and also the equations related to impedance structures are expressed. Then, using the rotational symmetry features and the method of moment, unknown currents are written as an expansion of known functions with unknown coefficients. These functions are local in the longitudinal dimension and a Fourier series in the azimuthal dimension. As a result, the problem is reduced to a set of two-dimensional problems that are very effective in reducing time and memory compared to the method of moment with RWG basis functions. Finally, the results obtained from the mentioned method are compared with the results obtained from commercial software in terms of accuracy and speed. Key Words : radar cross section (RCS) ,impedance boundary conditions, body of revolution (BOR).