The electric and optical properties were studied in Sb2Te3 with different thickness. It reveals the same resistivity at measured temperatures, but shows a larger magnetoresistance ratio at thicker flakes. All measured data conformed to a linear correlation between magnetoresistance ratio which is one-order enhanced, and mobility over a wide mobility range. A higher photocurrent response is observed in thicker flakes. These results support that the thickness enhances the effective carrier mobility which leads to magneto-transport and optic properties enhancement.