Polymerization pressure has a direct effect on the synthesis of syndiotactic polystyrene (s-PS) with metallocene as a catalyst. The polymerization rate, yield rate, and average molecular weight show a linear relationship with pressure, that is, they all increase with increased polymerization pressure. However, under 1000 psi, the yield of s-PS increases with polymerization duration while the yield rate decreases. As a whole, this syndiotactic polymerization proceeds relatively fast in comparison with ordinary vinyl polymerization. Optimal conditions (pressure, temperature, and duration) for the synthesis of s-PS have been explored.