Objective:To analyze the correlation between preoperative frailty and postoperative delirium (PD) in elderly patients undergoing abdominal surgery.Methods:From May 2019 to July 2021, a total of 435 elderly patients undergoing abdominal surgery in Jinhua Hospital of Traditional Chinese Medicine Affiliated to Zhejiang University of Traditional Chinese Medicine were selected by convenience sampling and divided into frailty group ( n=107) and non-frailty group ( n=328 ) using the Fried Frailty Phenotype scores before operation. Confusion Assessment Method was used to evaluate the occurrence of PD in 1 to 3 days after surgery. ROC curve was used to analyze the predictive value of the Fried Frailty Phenotype scores in PD. Results:A total of 80 cases of 435 patients developed PD, and the incidence of PD was 18.39%. The incidence of PD in frailty group was 40.19% (43/107) , and that in non-frailty group was 11.28% (37/328) , and the difference was statistically significant ( P<0.05) . After adjusting for age, living alone, American Society of Anesthesiologists classification, education level and preoperative Mini-Mental State Examination scores, the risk of PD in frailty group was higher than that in non-frailty group ( OR=4.761, 95% CI: 1.428-15.872) . The area under the ROC curve of the Fried Frailty Phenotype scores in predicting PD was 0.716 (95% CI: 0.647-0.785) . Conclusions:Preoperative frailty in elderly patients undergoing abdominal surgery can increase the risk of PD and predict the occurrence of PD.