Highly flexible nanocomposites based on room temperature vulcanizing (RTV) silicon rubber, and conductive nano system comprised of high structure carbon black (CB) and graphite nano plates (GNP) were fabricated by solution processing method. The synergistic characteristic of this nano system upon the involved electromagnetic interference shielding mechanisms of prepared composites was investigated. Electrical properties and EMI shielding efficiency of nanocomposites generated by various ratios of CB/GNP were measured and compared with the binary nanocomposites based on SR/CB and SR/GNP. The composites prepared by SR/CB showed higher electrical conductivity and lower percolation threshold than composites based on SR/GNP. However, despite of higher aspect ratio of GNP, the electrical properties of the hybrid based composites showed to be governed by the major filler phase and synergistic characteristic was not exhibited by hybrid filled nanocomposites. AC electrical conductivity and dielectric characteristic of the all prepared nanocomposites were evaluated as a function of fillers ratio within frequency range of 100-105Hz. For all binary and ternary nanocomposites ac conductivity showed increasing by frequency below percolation threshold without plateau (nonohmic conduction) , whereas above percolation threshold ac conductivity showed plateau within low frequency region, but sudden increase within high frequency region indicating nonohmic conductivity. Dielectric and electrical analysis suggested that, above percolation threshold direct contact plays as the main mechanism for electric charge current throughout SR phase for all nanocomposites. EMI shielding effectiveness measurement results within X-band frequency revealed that absorption loss is dominant mechanism for the attenuation of the intensity of incident electromagnetic wave in all nanocomposites generated by SR/CB, SR/GN and SR/CB/GN nano systems.