Objective To develop and validate a nomogram for predicting postoperative delirium among patients with Stanford type B aortic dissection after surgery. Methods In this retrospective cohort study, 559 patients with Stanford type B aortic dissection who underwent treatment from January 2019 to March 2021 were included.Lasso regression method was applied to select useful predictive variables associated with postoperative delirium.A multivariable Cox regression model using a backward stepwise approach was conducted to further explore predictors for postoperative delirium.A nomogram based on these predictors was developed and an internal validation using a bootstrap technique with 1000 resamples was applied. Results The incidence of postoperative delirium was 14.49%. Age ≥60 years, presenting with syncope, neutrophil count ＞6.3×109/L at admission, ICU admission, and postoperative estimated glomerular filtration rate ＜90 mL/（min·1.73 m2） were selected as predictors.The nomogram based on the 5 predictors demonstrated good discriminative ability with a C-index of 0.774 in the primary cohort and 0.762 in the internal bootstrap validation.The 1-day, 3-day and 7-day AUCs were 0.776 0.771 and 0.778 respectively. The calibration plots for 1-day, 3-day and 7-day postoperative delirium also demonstrated good agreement between the prediction results and actual observations. Conclusion This nomogram which has good predictive values thanks to 5 predictors, can help healthcare professionals identify the risk of postoperative delirium in patients with Stanford type B aortic dissection and provide reference for prevention and treatment of post-operative delirium in clinical work.