Abstract: Insomnia, as a globally prevalent sleep disorder, has become one of the major health problems in modern society. More and more studies have shown that insomnia is not only the result of physiological mechanisms, but also one where cognitive mechanisms play an important role in the formation and maintenance of insomnia. The article first retrieves existing relevant literature in PubMed and CNKI databases to organize cognitive theoretical models of insomnia and relevant scales associated with its three major cognitive psychological mechanisms: cognitive beliefs, metacognition, and neurocognition. It then conducts a secondary search for literature published in the past decade in PubMed and CNKI databases on the interactions of these three cognitive mechanisms, and draws a relational model diagram of insomnia’s three cognitive mechanisms to demonstrate the interaction among cognitive beliefs, metacognitive mechanisms, and neurocognitive mechanisms in insomniacs, thereby providing a theoretical basis for clinical treatment and future research.