Postoperative delirium (POD) is an acute disorder of the central nervous system, which is brief and reversible, causing the increase of postoperative complications and poor prognosis, especially in the elderly. The purpose of this paper is to summarize and conclude the articles on the relationship between preoperative sleep disorder and POD these years. This review summarizes the epidemiology of sleep disorder and POD in the elderly, the possible mechanism of sleep disorder causing POD, the measures for preventing POD by improving preoperative sleep quality. Because of the limited evidence and studies, the relationship between preoperative sleep disorders and POD in the elderly needs to be more explored in the future, which might provide new ideas for the clinic.