Electrofused magnesia, also known as electrofused magnesia, is not only used as the raw material of refractory high-tech products, but also used in power industry, aerospace industry and nuclear industry. Compared with sintered magnesia, electrofused magnesia is mostly made of high-grade natural magnesite and lightly fired magnesia, which is heated and fused in a high-temperature arc furnace, and the melt is naturally cooled. The main crystal phase magnesite first crystallizes freely from the melt, grows in size, has well-developed grains, large crystals, high degree of direct bonding, and dense structure. This structural characteristic makes electrofused magnesia more resistant to high temperature than sintered magnesia. It can be stable under 2300℃ in oxidizing atmosphere, and its high-temperature structural strength, slag resistance and hydration resistance at room temperature are superior to sintered magnesia.