The segregation behavior of silica in natural rubber (NR)/ styrene butadiene rubber (SBR) blends was investigated by dielectric relaxation spectrum, Fourier transform infrared spectrum and dynamic mechanical analysis. And it was detected quantitatively. The results show that the silica is easy to locate at NR phase. It is independent on the ratio between NR and SBR. The segregation behavior is not only related to fillerpolymer interaction, but also relates to silica network structure with different sizes, which are formed in different rubber phases. The results for silica filled NR/SBR vulcanizates with different ratios between NR and SBR show that the silica is still easy to locate at NR phase. The quantitative results between compounds and vulcanizates are different, which indicate that the vulcanization process has a significant effect on the filler segregation behavior.