Abstract: Adeno-associated virus (AAV)-mediated gene therapy has led to a breakthrough in the clinical treatment of single-gene disorder. Optimizing AAV vector through capsid modification to obtain AAV vector with cell targeting, high transduction efficiency and low or no immunogenicity has become one of the focuses of gene therapy research. At present, AAV capsid is mainly modified and reconstructed by rational design, directed evolution and chemical modification. Here, we review the biological characteristics of AAV and the recent research advances in the modification of AAV capsid, and discuss the challenges in this field.