With the development of technology of surgery and human life span increasing, more and more elderly patients have the opportunities to underwent surgery. Therefore, the complications of such kinds of patients get more attention. Postoperative Delirium (POD) is a common postoperative complication especially in elderly patients. This review summarized genetic risk factors,physiological and immunological changes associated with POD, with a focus on the biomarkers of POD in recent studies. This review introduces the delirium biomarkers of the cholinergic neurons in nerve system, inflammatory response, neurotransmitters, brain injury markers, neurotrophic factors and so on. We try to establish the predictive model of delirium so that providing theoretical basis for promoting diagnosis and treatment of POD.