It is become a very important area to measure the quality of agricultural products for the quickly development of agricultural and food process. Non-destructive technology of food has become the focus of researches in food science field. Inspection by using the dielectric property is widely adopted and has unique advantages in quality inspecting and grading. The research advances in non-destructive technology of food by dielectric property is reviewed from the measurement of moisture, soluble solid content, freshness and online evaluation of drying, oil-frying, fermentative, freezing process of food. Some new ideas of study on non-destructive detection in the future are pointed out.