Electron spin resonance is a new technology application of study the electron structure and dynamics of the species which have unpaired electron. Nowadays ESR has been widely applied in biology and medical science. For example it is used to explore the catalytic mechanism and structure of metal proteins and analyze the structure and function of single molecular magnetism which has metals and residues. At present, one of the microcosmic ESR methods which based on NV centers is applied to explore the object at the nano-scale. The single molecule ESR spectrum has been detected through this technique. In this paper，the application principle and development of ESR technology were summarized, which could be taken as reference for analysis of the protein molecule structure and dynamics, determine the radical reaction process，location of spin-label molecular and other fields.