This study was investigated on the physical properties of synthetic rubber compounds containing silica and silane copuled silica. Surface area and pore volume of silane copuled silica appeared to be low compared with those of pure silica because silane coupling agent blocks the pore of silica surface during silanization reaction. Silica with large surface area and high structure showed the short scorch time(t_5) and rapid cure rate. The silane coupled silica showed the shorter scorch time and more rapid cure rate than pure silica because of the effect of sulfur in the silane coupling agent.(Si 69). They high value of N₂SA minus CTAB compared with surface area acid structure of silica showed the high 300% modulus. Also, the surface area and structure of silica did not, affected the amount of PICO loss that indicate the abrasion resistance but affected the amount of cut and chip loss.