The sulfur containing silanes [bis (triethoxysilyipropyl)tetrasulfide (Till and bis(triethoxysilyipropyl)disulfide (TESPD)] and silica were compounded in the natural rubber (NR) and their effects with respect to the viscosity, heat generation, power consumption, vulcanization, dynamic, mechanical, heat build-up (HBU), and blowout (BO). properties and the silica agglomerate break down were compared. The treatment of the TESPT and the TESPD on silica surface lowered the viscosity of each compound and their effects were more significant on the S2 (Silica/TESPD/NR) compound than the S4 (Silica/TESPT/NR) compound. After vulcanization, both compounds improved their mechanical properties. The stiffness of the compound was more significant on the S4 than the S2 compound. The silica agglomerate size of each compound was reduced after vulcanization.