Proteins are the workhorses of cells,their biological functions are regulated by their dynamic structures,interactions with other biomolecules and many other factors.Gaining detailed structural information of proteins or protein complexes is crucial to decipher the molecular mechanisms of important biological processes.Hydrogen deuterium exchange mass spectrometry(HDX-MS) is not only a powerful tool for studying the dynamic changes of protein structures and protein ligand/protein interactions,but also an important complement to traditional biophysical approaches.In this review,the basic principles,mechanism,experimental methods and recent development of HDX-MS are presented,especially focusing on its applications in protein dynamics,protein-small molecule interactions and protein-protein interactions.