Drying is one of the methods to keep the substance from spoiling. There are many drying methods, such as sun drying, boiling, spray drying and vacuum drying. However, most of the volatile components will be lost, and some heat-sensitive substances such as protein and vitamins will be denatured. Therefore, the properties of the dried product are quite different from those before drying. The freeze-drying method is different from the above drying methods, which can preserve more nutrients and the original shape of the food. Freeze-dried pet food is a pet food production process based on the characteristics of freeze-drying technology.