Vacuum freeze-drying technology, commonly referred to as freeze-drying, is the study of the heat and mass transfer processes, characteristics, and principles of drying materials under a vacuum environment. It is an interdisciplinary comprehensive technology. The development of freeze-drying technology requires support from technologies such as vacuum refrigeration, heating, mechanical transmission, and automatic control.

The principle of vacuum freeze-drying is based on the phase diagram of water. Below the triple point pressure of water (610.5 Pa), no liquid water exists, and solid ice can directly sublime into water vapor. If heat is provided at this time, the ice can absorb heat and sublime into a gas, thereby dehydrating the substance, hence also known as freeze-sublimation drying.