Abstract: Brain-targeted delivery plays an important role in the diagnosis and treatment of neurological diseases, but the existence of blood brain barrier (BBB) limits the development of brain-targeted delivery. As cell-derived nanovesicles, exosomes can participate in the transportation of substances between cells to mediate the communication between cells to play a biological regulatory role in vivo. Due to the low immunogenicity, low toxicity, high engineering and natural crossing over BBB, exosomes play an important role in brain-targeted delivery. In this paper, the composition of exosomes, the mechanism of brain targeted delivery and its role in various brain diseases are systematically described.