Adeno-associated viruses (AAV) are small viruses with single-stranded DNA genomes that are capable of infecting both dividing and non-dividing cells. Adenoviruses or herpesviruses are usually required to help them replicate and amplify in vivo. Recombinant adeno-associated virus (rAAV) is a hybrid viral vector that utilizes the AAV type 2 genome in combination with the genomes of different serotypes of capsid proteins. The CDS region of the target gene or the RNAi interference sequence can be inserted into the rAAV expression plasmid, which packages the virus and then infects the cell to complete the manipulation of the target gene. In humans and mice, AAV infection can mediate targeted integration of exogenous genes at a low frequency (not higher than 2%), with insertion typically on the short arm of chromosome 19 (AAV S1 in the human genome and the ROSA26 locus in the mouse). The viral genome forms an accompaniment within the infected cell without integration. Adeno-associated viruses are widely used in the neurological field, cardiovascular field, liver, muscle, lung, and other fields, and their main directions of application lie in localized and holistic injections.