The dispersion law, density states of phonons, thermodynamics properties and thermal conductivity was analyzed in this paper. It has been shown that at low temperatures, thermal conductivity of thin lm is considerably lower that of bulk-structure. It turned out that phonons in thin lm require activation energy for exciting. This leads to extremely low specic heat and specic conductivity at low temperatures. Consequences of quoted facts were discussed in detail and their inuence on kinetic and thermodynamic properties of thin lms is estimated.