Exosomes are secreted by cells，which has a nano-sized vesicular structure with a diameter of about 40-100 nm and is essentially a lipid bimolecular vesicle. Its main components and contents are mainly proteins，nucleic acids，and lipids. Not only in physiological but also in pathological conditions，exosomes can be secreted by most cells and exist in almost all body fluids，which is an important way of information exchange and material exchange. This review clarified the general characteristics of exosomes. The information exchange mode of exosomes in cells and the information exchange between central nervous cells were described in detail. The role of exosomes as molecular markers，particularly in neurodegenerative diseases，was explored. The drug treatment and gene therapy of exosomes in the central nervous system were briefly described.