The effect of the surface treatment of clay nanoparticles on the Styrene -butadiene Rubber (SBR) /clay nanocomposite was studied. The treatment process was done by coating the clay by trimethylolpropane tiracrylate (TMPTA) then irradiated by 100 kGy of an electron beam accelerator. Two distinct groups from SBR/ Nano treated and non-treated clay composites were prepared to be compared with each other. The effect of clay nanoparticles loading and treatment process on the rubber was investigated by Dielectric properties, Thermal gravimetric analysis (TGA), thermomechanical analysis (TMA), and volume fraction dependence. It is found that by the addition of clay, there is a decrease in the amorphous contents of the samples owing to the detectable increase in the relaxation time as observed from the dielectric relaxation spectroscopy measurements. The depolarizing factor, calculated by Tasangaris equation indicates the change of the shape of clay particles from oblate ellipsoids to the shape of a sphere with the applied frequency. The activation energy was calculated for all samples and show that it decreases with the treatment process while increased with the increase of the clay. Furthermore, the weight loss has an undulatory behavior with the clay increasing and treatment process.