Protein dynamics analysis is central to elucidating biological functions. Owing to its unique combination of temporal resolution and structural sensitivity, infrared spectroscopy has emerged as a pivotal tool for investigating protein dynamical processes. This review systematically summarizes the fundamental principles, cutting-edge technologies, and practical applications of infrared spectroscopy in the analysis of protein dynamic structures. The temporal resolution capability of infrared spectroscopy has achieved full temporal scale coverage, ranging from the femtosecond to the millisecond level. This capability enables the capture of complete dynamic processes of proteins, spanning from ultrafast relaxation to conformational rearrangement. Two-dimensional infrared spectroscopy further improves spectral resolution and enhances the analytical capacity for complex protein systems. Infrared spectroscopy has been successfully applied to multiple research fields, including protein folding, ligand binding, and membrane protein dynamics. Notably, it has yielded significant progress in the investigation of critical biological processes such as the folding mechanism of amyloid fibrils, ligand binding of heme proteins, and proton transfer of membrane proteins. In the future, with the development of novel infrared probes and the integration of artificial intelligence technologies, infrared spectroscopy will exhibit greater application potential in the field of protein dynamics analysis.