Abstract: Factors affecting reinforcement of high temperature vulcanizates were investigated using(interfacial) bound rubber samples of silicon rubber reinforced by fumed silica nanoparticles with different surface properties.Its interfacial action was analyzed by field emission scanning electron micrographs.Network of SiO_2 nanoparticles formed the framework of the three-dimensional structure of bound rubber;the best reinforcement for silicon rubber was achieved using SiO_2 nanoparticles with the highest structural performance.The largest effective reinforcement volume and best reinforcement would be achieved with a SiO_2 filler content of 0.26~0.29(mass fraction) and/or 1.1 to 1.4 OH groups.