Functional Near-Infrared Spectroscopy (fNIRS) is a non-invasive technique for studying the operative organization of the human brain by measuring haemodynamic responses to neuronal activation in the cerebral cortex. Functional near-infrared spectroscopy (fNIRS) has become an important research tool for exploring the neural mechanisms of psychology gradually. First, this article introduces the concepts and basic principles of functional near-infrared and technology, and introduces the processing methods of physiological interference and motion artifact signals in the near-infrared spectroscopy technology. Then, it briefly introduces the application of some functional near-infrared technology in the field of psychology and its combined use with other imaging technologies. Finally, the advantages and disadvantages of functional near-infrared technology are discussed.