Because the whole process of metal melting and casting in the vacuum casting machine is completed under the protective conditions such as vacuum inertia, when the metal melts in vacuum at high temperature, the equipment is opened and sealed for vacuum inert gas pressure casting, and the gas chamber of pressurized inert gas is released. By filling inert gas, the whole process is isolated from the air, and molten metal falls into the gypsum mold through the leakage door of the crucible, thus completely eliminating any form of pores or shrinkage cavities and effectively avoiding oxidation. Increasing the pressure of inert gas means that the whole casting process is under pressure, and the whole casting process is carried out under vacuum pressure, so that the cast jewelry has high density and bright surface, achieving the effect of basically no Chacon and no oxidation.