XPS foam board, named as polystyrene extrusion plastic board (XPS for short) has a flawless closed-pore alveolate structure. Its performances such as the density, water absorption, coefficient of heat conducting and the coefficient of steam pervasion and so on have advantage over those of other board in heat preservation materials and they have the characteristics of strong intensity, light material, airlight, anticorrosion, aging resistance, low cost, etc. It has been used widely in the fields of heat preservation and heat insulation in the construction industry, frost resistance of the highway, railway, airport, square and household fitment. It is generally acknowledged and the best heat preservation material in the market at present.