With the escalating prevalence of diabetes and obesity, resistant dextrin, renowned for its prebiotic properties and blood glucose-lowering physiological activity, has garnered significant attention. Resistant dextrin, a low-calorie, indigestible water-soluble dietary fiber processed from starch, has high solubility, low molecular weight, and good thermal stability. The established method for its preparation involves a combination of acid heat treatment and enzymatic purification. Within the human body, resistant dextrin confers numerous health benefits. It promotes a balanced intestinal microbiome, regulates blood glucose and lipid metabolism, and enhances satiety. Additionally, it exerts positive influences on the intestinal environment, aids in weight management, and alleviates chronic conditions, particularly diabetes. In the food industry, resistant dextrin is widely employed as a functional food additive to enhance the nutritional value and health benefits of various food products. However, there is a need for greater clarity regarding the structural characteristics of resistant dextrin and the potential interplay between its structure and physiological activity. This paper comprehensively reviews the preparation methods, structural properties, health benefits, and application areas of resistant dextrin. Additionally, it anticipates future trends in its development. The primary objective of this review is to offer theoretical guidance and fresh perspectives for further research, the innovation of functional products, and the expanded utilization of resistant dextrin.