Abstract: Adeno-associated virus (AAV) is a common viral vector used in gene therapy.Because of its high safety and its ability to target a variety of cells, it has been widely used in preclinical and clinical studies.However, during the design and production, AAV vectors have many key quality attributes that affect their safety and efficacy.The development and application of biological mass spectrometry technology provides a convenient platform for the research on biological macromolecules, especially in the aspects of protein sequence, structure and interaction.For AAV vectors, mass spectrometry can facilitate the determination or characterization of capsid protein ratio, post-translational modification, serotype, and empty capsid ratio, thus assisting in the quality control of AAV vectors.Compared with the existing methods, mass spectrometry has the advantages of smaller amount of sample size, faster and more sensitive analysis, being more suitable for the analysis of complete AAV vectors with higher mass resolution, and can distinguish empty capsids, full capsids and partial capsids.In the future, mass spectrometry technology is expected to play a more important role in the design and production of AAV vectors through the coupling of more efficient protein separation technology with mass spectrometry, the development of new information processing software platforms and new mass spectrometry detection techniques.