Freeze drying is a technique of drying using the principle of sublimation. It is a process in which the dried material is quickly frozen at a low temperature, and then in a suitable vacuum environment, the frozen water molecules are directly sublimated into water vapor to discharge. The raw material is always in a frozen state before drying, and the ice crystals are evenly distributed in the raw material, The sublimation process will not be concentrated due to dehydration, and side effects such as foam and oxidation caused by water vapor will be avoided. The dried substance is porous in the form like dried sponge, and its volume is basically unchanged, it is easily soluble in water and restored to its original shape, preventing the physical, chemical and biological denaturation of the dried substance to the greatest extent. The freeze dryer is mainly composed of refrigeration system, vacuum system, heating system and control system. The main components are drying box, condenser, refrigeration unit, vacuum pump, heating and cooling device etc., after pre-treatment the material is sent to the quick-freezing bin to freeze, then sent to the drying bin for sublimation and dehydration, and then packed in the post-processing workshop. The vacuum system establishes a low-pressure condition for the sublimation drying chamber, the heating system provides sublimation latent heat to the material, and the refrigeration system provides the required cooling capacity to the cold trap and drying chamber. The main body is made of high-quality 304 stainless steel, which is easy to operate and maintain.