Microwave drying is a new drying method. During drying, the microwave energy directly acts on the medium molecules to convert them into heat energy. Because the microwave has the penetrating property to heat the inside and outside of the medium at the same time, without the need for heat conduction, the heating speed is very fast. For foods with a water content of less than 30%, the drying speed can be shortened by hundreds of times. At the same time, regardless of the shape of the object, because the medium of the object is heated inside and outside at the same time, the temperature difference between the inside and outside of the material is small and the heating is uniform, so that the external Coke will not be generated in the conventional heating, which greatly improves the drying quality. Microwave drying is different from traditional drying, and its heat conduction direction is the same as the moisture diffusion direction. Compared with the traditional drying method, it has the advantages of high drying rate, energy saving, high production efficiency, uniform drying, clean production, easy to realize automatic control and improve product quality, so it is paid more and more attention in various fields of drying. Drying process is widely used in production and life. The purpose of drying is to remove the water or solvent in some raw materials, semi-finished products and finished products, so as to facilitate processing, use, transportation and storage.