Abstract: Dietary fiber is known as‘the seventh largest nutrient in the human body’, and plays an important role in the regulation of human health. In this review, the definition, classification, physical and chemical properties, physiological functions and influencing factors, preparation methods and application in food processing of dietary fiber are summarized. In view of the current research status of dietary fiber, the key problems to be solved are put forward in order to provide theoretical reference for the wide application of dietary fiber in food.