An approach to modeling processes of deformation of materials containing pores of different sizes: from macroscopic pores with the diameter of several hundreds of microns or several millimeters to micropores of several hundreds of nanometers is presented. Different models of mechanics of the deformed solid body are used to investigate the stressed-strained state of materials at different scale levels of the microstructure. The multipole expansion method is used to describe deformation of the medium, containing macro-sized pores. A model of the Aero-Kuvshinsky quasicontinuum for porous media is used to estimate the distribution in the microporous medium. The problem on the isolated micro-sized spherical pore is solved within the framework of the gradient elasticity theory. Such solution makes it possible to verify the medium stressed-strained state in the region of the micropore, depending on its size. Moreover, this solution can be used to show the range of pore sizes, for which the solution of the classical elasticity theory is valid.