Exosomes are extracellular vesicles with plasma membrane. They are produced intracellularly and then secreted out of the cells. Almost all types of cells in human bodies can produce and excrete exosomes. Exosomes carry a variety of signal proteins, mRNA, miRNA, lncRNA and their degradation fragments. Due to the protection of lipid membrane, these components have biological activity and get involved in the process of cell migration, apoptosis and proliferation, and can modulate the function of the recipient cells. As an important cell-cell signal carrier, exosomes are involved in the development of many kidney diseases. This article reviewed the biological characteristics of exosomes and their roles in acute kidney injury.