Novel optically active methacrylates polymer with controlled molecular weight have been prepared simply by opening ring reaction of poly(glycidyl methacrylate) and S-(-)-alpha-methylbenzylamine. The structure of the novel optically active methacrylates polymer was characterized by FT-IR, and chiroptical properties of the polymer were characterized by polarimeter and circular dichroism spectrum. Thermogravimetry analysis and differential scanning calorimetry were employed to examine the thermal properties of the polymer. This preparation process was simple and the racemization of optically active monomers in preparation can be avoided. The molecular weight of optically active methacrylates polymer could be controlled by molecular weight of poly(glycidyl methacrylate) prepared by atom transfer radical polymerization.