Polystyrene (PS) is a thermoplastic resin, which is colorless, odorless, tasteless and shiny transparent crystal. It has chemical corrosion resistance, water resistance, excellent electrical insulation and high-frequency dielectric properties. Its disadvantages are low heat resistance, poor light resistance, brittle and easy to stress cracking. There are four main categories of PS: GPPS (general grade PS resin), hips (impact grade PS resin), EPS (foamable PS resin) and SPS (inter gauge PS resin). There are three production methods of PS: bulk method, suspension method and solution method. Among them, bulk polymerization process is the main method to produce PS in industry. In the next five years, the global polystyrene market demand is expected to grow at an average annual rate of 2%, while the Chinese market will become a fast-growing region with an annual growth rate of 5.9%.