To further explore the mechanism of postoperative delirium and screen for valuable signaling molecules, we screened using proteomic techniques and verified by subsequent experimental techniques that high expression of MAGI-2 in peripheral blood was an important marker of postoperative delirium, and the level of MAGI-2 in peripheral blood was significantly higher in POD patients than in non-POD patients. The gene discussed is MAGI2; the disease is delirium.