The annual domestic output of magnesium oxide is about 12 million tons. One of the main uses of magnesium oxide is as a flame retardant, a traditional flame retardant material, a flame retardant mixture of halogen-containing polymers or halogen-containing flame retardants. However, in the event of a fire, a large amount of smoke and toxic corrosive gases are generated due to thermal decomposition and combustion, which hinders fire fighting and personnel evacuation and corrosion of instruments and equipment. In particular, it has been found that more than 80% of fatal accidents in fires are caused by heavy smoke and toxic gases produced by materials. Therefore, in addition to flame retardant efficiency, low smoke and low toxicity are also essential indicators of flame retardants. The development of China's flame retardant industry is extremely unbalanced, and the proportion of chlorine-based flame retardants is heavier. It is the first of all flame retardants, and chlorinated paraffin has a monopoly position. However, chlorine-based flame retardants release toxic gases when they act, which is far from the non-toxic and efficient pursuit of modern life. Therefore, in order to comply with the development trend of low smoke, low toxicity and pollution-free of the world's flame retardants, the development, production and application of magnesium oxide flame retardants are imperative.