Abstract: Exosomes are extracellular vesicles that contain various proteins and cellular regulatory factors, which participate in intercellular information transfer and regulate cell growth and physiological processes. Exosomes can indicate the level of gene expression of cells in immunological studies at the cellular level, as their functional variability is closely related to the type and state of the cells that secrete them.Viruses are small and simple in structure. They complete self-replication and escape host immunity by involving a complex immunoregulatory network. As a new focus of information exchange, the role of exosomes as“messengers”in this regulatory network deserves attention. MicroRNAs also play a crucial regulatory role in intercellular information exchange. After being selectively sorted into exosomes, as one of the exosomeloaded cargoes, exosomal microRNA can regulate biological functions more stably and participate in the regulation of viral immunity. In this paper, the composition, mechanism, and content of exosomes are briefly introduced. Taking the exosomal miRNA with a wide research range and more research content as a starting point, it is focused on its dual role in viral immunity. Understanding the regulatory role of exosomal microRNA in the same or different viruses would be of great significance to further analyze the mechanism of virus invasion into the host.

Key words: exosomes , extracellular vesicles , microRNA , viral immunity