A thiazole type accelerator MBT (2-mercapto benzothiazole) was added into silica filled natural rubber (NR) compound with various concentrations (0, 1, 2, 3, 4 phr). The effects of MBT on the cure rate, mechanical property, degree of rubber-filler interaction (${alpha}_F$), crosslinking density, and viscoelastic property ($tan{delta}$) were investigated. As accelerator concentration increased, the $t_{s2}$ and $t_{90}$ decreased and the crosslinking density and modulus at 300% elongation increased. The tensile strength and elongation increased up to 3 phr and no further increased at 4 phr. The $tan{delta}$ value measured at room temperature was higher than that of the $70^{circ}C$. The ${alpha}_F$ value was not affected by the addition of MBT. The mechanisms for the vulcanization rate were reviewed.