Abstract: Postoperative delirium (POD) is one of the most common postoperative complications in elderly patients. Exploring its pathogenesis is helpful for the evaluation, diagnosis and treatment of POD, and the biomarkers of delirium are helpful for us to further clarify the pathogenesis of POD. This article is to review the progress in the application of inflammatory mediators, cholinergic markers, nerve injury markers, melatonin and metabolic markers in the diagnosis and treatment of postoperative delirium in elderly patients.