Vacuum freeze-drying is one of the most gentle ways to dry. It is based on the sublimation principle, that is, the solid phase directly into the gas phase of this physical phenomenon. The freeze-dried material is placed in a vacuum drying chamber for drying, and the water vapor produced by the cold trap is condensed to form ice, so as to achieve the purpose of eliminating water vapor. Vacuum pump is used to discharge the air in the drying room, not including water vapor. The baffle plate is provided with a heating device, and the heat is transferred to the material 4 through the conduction function to provide the energy needed for sublimation. When the free water in the material is sublimated, the internal bound water can also be removed from the material at a very low vacuum.