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