The construction of the complex model of granule formation of powdered materials in drum granulators taking into account the anisotropy of structure and laminating on the surface is considered. It has been noted that granule formation proceeds in some stages depending on relaxation time of embryo formation. On the base of the model a graphic interpretation of the process of laminating of powder on the surface is cited. Rheological model of compact of granules under the action of external deformation stresses allowing to estimate the change of porosity and density in time of arrival is presented. The comparison of calculation and experimental results for the evolution of distribution of granules on sizes has been presented. (C) 2009 Elsevier B.V. All rights reserved.