Exosomes are nanoscale (40-160 nm in diameter) extracellular vesicles that play a role in cell signal transduction， immune response and antigen presentation. They can be isolated from various body fluids， including serum， saliva， urine， cerebrospinal fluid and emulsion， etc. Milk-derived exosomes are endogenous delivery vehicles which contain a variety of functional molecules such as proteins and miRNA， many of which are related to human immune function. Milk-derived exosomes can be absorbed by human intestine and exert healthy effects through ingestion of milk. This article summarizes domestic and foreign reports on the relationship between milk-derived exosomes and microorganisms， as well as the research results of our team. In this article， the biogenesis process and main components of exosomes， the relationship between exosomes and pathogenic microbial infection， and the effects of milk-derived exosomes on intestinal microorganisms were expounded. It provides a reference for studying the nutritional and health effects of milk-derived exosomes on human body.