FIELD: heat power engineering. SUBSTANCE: invention relates to the field of creation heat-conducting materials. Polymer composite heat-conducting paste is proposed for mating heat-stressed various devices and parts that contains a heat-conducting inorganic filler selected from aluminum nitride, silicon carbide and/or graphite, a binder in the form of organic polydimethylsiloxane, and a fiber or nanofiber modifier selected from carbon nanotubes and fiber silicon taken in the amount from 0.1 to 15% per weight of inorganic filler powder. EFFECT: increase in heat conductivity due to the formation of percolation clusters in the paste volume. 2 cl, 2 dwg, 4 ex.