Magnesium oxide ceramics belong to the cubic crystal system, the melting point is about 2800 degree C, the theoretical density is 3.56~3.65g/cm^3, the Mohs hardness is 5-6, the specific volume resistance value is higher at high temperature, and it has good electrical insulation properties. Since magnesium oxide is volatile above 2300 degree C, its use of magnesium oxide ceramic products should be restricted below 2200 degree C; because of its strong resistance to alkaline metal slag, crucible products produced by special methods have many advantages. This product has excellent thermo-chemical properties and stability against metals, and can be used for smelting non-ferrous metals and precious metals, such as platinum, rhodium, iridium, and smelting high-purity radioactive metals such as uranium, thorium alloys, iron and their alloys and so on. It can also be used as high temperature thermocouple protection tube and high temperature furnace lining material, etc. The magnesium oxide crucible products produced by this method also have good hydration resistance and can be produced in small batches for special fields.