Objective To analyze the risk factors for delirium of the Stanford A aortic dissection patients after surgery. Method We retrospectively analyzed the clinical data of 335 patients with type A aortic dissection in Guangdong Cardiac Institution from January 2012 through December 2014. There were 280 males and 55 females. The average of age was 48.5±10.3 years. Delirium status of the patients were evaluated based on confusion assessment method for intensive care unit (CAM-ICU). The patients were divided into two groups including a delirium group and a control group. We tried to find the risk factors for postoperative delirium. Results There were 169 patients of delirium with a incident rate of 50.4%. One-way analysis of variance and multivariate analysis indicated that pre-operative D-dimer level (OR=2.480, 95% CI 1.347-4.564, P<0.01), the minimum mean arterial pressure during operation (OR=0.667, 95% CI 0.612-0.727, P<0.01), the postoperative ventilation time (OR=2.771, 95% CI 1.506-5.101, P<0.01) and the postoperative acute kidney failure (OR=1.911, 95% CI 1.065-3.430, P<0.05) were the independent risk factors for delirium of the Stanford A aortic dissection patient after surgery. Conclusion The incident rate of postoperative delirium of the Standford A aortic dissection patient is relatively high. Patients in this study with elevated pre-operative D-dimer level, lower intraoperative mean arterial pressure, longer postoperative ventilation and combination of acute kidney failure have a higher rate of postoperative delirium. Better understanding and intervention of these factors are meaningful to reduce the occurrence of postoperative delirium.