Expanded polystyrene boards are made by mixing resin with polymers, adding a catalyst during the heating process, and then extruding them into solid foam boards with continuous closed-cell foam structure. These boards feature independent, sealed bubble structures, and are an environmentally friendly insulation material with excellent properties such as high compressive strength, low water absorption, moisture resistance, impermeability, lightweight, corrosion resistance, and ultra-anti-aging (virtually no aging after long-term use) with a low thermal conductivity coefficient.