Annotation: The calculation method of the radiation characteristics obtaining has been proposed for octagonal aperture antenna with two-layer conic dielectric radome. For all that the method for radiation field calculation created early by authors is used. This method allows to calculate the radiation field for aperture cut in perfectly absorbing screen at the presence of arbitrary scatterer system (particularly, radome). Numerical results for radiation patterns of the aperture antenna with two-layer radome have been brought out for different parameters of layers. For that calculation the solving model problem about scattering plane electromagnetic wave by two-layer plane-parallel plate have been used.