The thermal properties of porous silicon and composite "PS-liquid" system have been investigated in this paper. Using the photoacoustic method the values of thermal conductivity of porous silicon and composite systems with liquid have been obtained. It is shown that the value of thermal conductivity "PS-liquid" substantially exceeds the value determined by the model of "parallel structures". The increase of thermal conductivity is due to the improvement of thermal contacts among the crystallites when introducing liquid into the pores.
