Abstract: With the rapid development of society, cardiac arrest has become a major public health problem worldwide. For cardiac arrest patients, the primary goal of cardiopulmonary resuscitation(CPR) is to ensure oxygen supply to the brain and prevent brain hypoxia injury. Recently, near infrared spectroscopy (NIRS) and its application in CPR has attracted widespread attention because it can monitor local oxygen saturation of frontal cortex brain tissue, and reflect the balance of oxygen supply and demand in real time. NIRS technology can be used to evaluate the quality of CPR, detect repeat arrest early, predict prognosis of patients, evaluate the level of autonomous regulation of cerebral blood flow, as well as monitor target temperature management and the treatment effect of patients with extracorporeal CPR. Hence, NIRS has good clinical application potential. This article mainly reviews the principle of NIRS and its application in CPR.