In recent years， the study of gut microbiota and intestinal homeostasis had been a hot topic in many fields of clinical medicine， biology and food nutrition. Intestinal mucosa was an important barrier for the body to resist the invasion of external pathogens and maintain intestinal homeostasis. Mucin played an important role in food nutrition as the main component of intestinal mucus. However， the functional characteristics and related studies of mucin were still unclear due to the particularity of intestinal mucus. There were no systematic summary and analysis between mucin and food nutrition. Therefore， this paper reviewed the structure， classification， biological activity of mucin and its relationship with food nutrition， in order to provide reference for the study of mucin in the field of intestinal health and food nutrition.