Scattering of THz radiation in inhomogeneous media is an important reason of reducing spectral information in received THz signal for different applications. Scattering of THz radiation in thin layers of dielectric material was studied, particularly, in fabric materials. A structure of different types of cloth fabric was studied, and mathematical model of fabric was suggested, which is a system of dielectric cylinders. Scattering of THz radiation was modeled numerically. Scattering cross-section and indicatrix were calculated, and then spectral transmittance was computed. During a set of experiments THz spectral transmittance of various fabric materials were obtained and numerical results were approved. The developed method for receiving scattering characteristics of different materials can be used for extracting useful information from received THz signal.