Xps extruded plastic sheet is a new type of building material which is widely used in China. This new type of environmental protection material uses waste plastic to turn waste into treasure, because of its excellent high strength, compression resistance, excellent heat insulation, light texture, easy to use, high-quality water-repellent, moisture-proof and environmental protection performance, stability, anti-corrosion good, become the construction industry to promote the new building materials. Widely used in wall and floor insulation. According to the requirements of the new edition GB8624-20l2"classification method of the burning properties of building materials" , the burning properties of fire-retardant extruded board and ordinary extruded board were tested respectively. The combustion performance of the fire-retardant extruded board is B 1B Class, which is difficult to burn, while that of the ordinary extruded board is B 3F Class, which belongs to the flammable material. Through the comparison of the combustion performance between the fire-retardant extruded board and the ordinary extruded board, it is found that the combustion grade of the extruded board can be raised from B3 to Bl through the fire-retardant extrusion treatment, and the fire-retardant effect is obvious, be Able to meet the actual application and the requirements of the relevant national standards. However, there is still a gap between the simulated fire environment and the real fire environment. Extruded plates containing flame retardant additives can prevent accidental fires caused by a small fire, such as a cigarette butt or cutting spark may not cause accidental fires on the extruded plates. However, in the actual fire environment, due to the effect of sustained fire source, the fire-retardant extruded board will still emit a lot of heat and toxic smoke, and the effect of fire-retardant agent will be very limited. Moreover, there are many problems in the production process of fire-retardant extruded board: The decomposition temperature of fire-retardant is lower than the processing temperature of extruded board, which will result in a large number of decomposition of fire-retardant, after decomposition, the strong acid not only corrodes the production equipment but also degrades the plastic, reduces the molecular weight of the extruded board and decreases the mechanical properties The decomposition of flame retardants can also cause the degradation of their flame retardancy, and in order to achieve flame retardancy, they have to use the method of supernormal addition of flame retardants, which results in waste and environmental damage, some manufacturers have adopted the method of lowering the processing temperature and producing fire-retardant extruded board at ultra-low temperature. Although this method has certain effect, it has not solved the problem fundamentally, and easy to cause equipment wear fast, board density high, thermal insulation Coefficient decline, is not conducive to the healthy development of extrusion board industry. With the continuous development of some new materials, new technologies and new processes, the research on the flame retardancy of extruded boards is also deepening, the flame retardant which was considered to have poor processability and low flame retardancy will be improved by improving its properties, and gradually meet the demand of modern extruded board flame retardancy.