Objective To investigate the incidence and related factors of postoperative delirium in elderly patients undergoing elective noncardiac surgery under general anesthesia. Methods Elderly patients aged ≥65 years old undergoing non-cardiac surgery under general anesthesia from December 31, 2017 to December 31, 2018 were retrospectively analyzed. The patients were divided into delirium group and control group according to whether delirium occurred after surgery. Paired t test was used to compare the laboratory test results between the delirium group and the control group. Logistic regression analysis was used to identify the independent risk factors for delirium after non-cardiac surgery in elderly patients. Results A total of 1 072 elderly patients undergoing elective non-cardiac surgery were enrolled in this study. Delirium occurred in 60 patients, and the incidence of delirium was 5.6%. Multivariate Logistic regression analysis showed that postoperative prothrombin time(PT), preoperative blood glucose, preoperative activated partial thromboplastin time(APTT) and postoperative C-reactive protein(CRP) were independent risk factors for delirium after non-cardiac surgery in elderly patients. Conclusions Postoperative PT, preoperative blood glucose, preoperative APTT and postoperative CRP are independent risk factors for POD in elderly patients undergoing non-cardiac surgery.