Microwave vacuum freeze dryer is an innovative high-tech product with excellent application performance. It has a new product concept and higher value in medicine, chemical industry and agricultural products processing. In the process of microwave vacuum freeze drying of materials, it is necessary to turn the drying chamber into a vacuum state, and then freeze and sublimate the materials. When freezing materials, the temperature is generally below - 20 ℃, but in actual operation, it should be determined according to the characteristics of different materials. When freeze-drying materials, it is necessary to provide sublimation heat for materials. Microwave is used to provide sublimation heat. This drying method is called microwave vacuum freeze-drying.