Objective    To investigate the predictive value of prognostic nutritional index (PNI) in complications after thoracoscopy-assisted radical resection of esophageal cancer. Methods    We collected the clinical data of patients who underwent thoracoscopy-assisted esophagectomy in the First Affiliated Hospital of Xinjiang Medical University from January 2015 to June 2020. The predictive value of PNI for postoperative complications was evaluated by establishing receiver operating characteristic (ROC) curve and the optimal cut-off point was determined. The patients were divided into a high PNI group and a low PNI group according to the cut-off point. The differences of baseline data and perioperative complications-related indicators between the two groups were compared and analyzed. Univariate and multivariate analyses were used to investigate the influence of PNI and other related indexes on postoperative complications. Results    A total of 116 patients were enrolled in this study, including 75 males and 41 females, aged 65 (58-69) years. The area under ROC curve was 0.647, and the optimal cut-off point was 51.9. According to the cut-off point, there were 45 patients in the high PNI group and 71 patients in the low PNI group. The overall complication rate (χ2=10.437, P=0.001) and the incidence of postoperative pulmonary infection (χ2=10.811, P=0.001) were statistically different between the two groups. The results of univariate analysis showed that the duration of ventilator use (Z=–3.136, P=0.002), serum albumin value (t=2.961, P=0.004), and PNI value (χ2=10.437, P=0.001) were the possible risk factors for postoperative complications after thoracoscopy-assisted esophagectomy. The results of multivariate analysis suggested that the duration of ventilator use (OR=1.015, P=0.002) and the history of drinking (OR=5.231, P=0.013) were independent risk factors for postoperative complications, and high PNI was the protective factor for postoperative complications (OR=0.243, P=0.047). Conclusion    PNI index has a certain value in predicting postoperative complications, which can quantify the preoperative nutritional and immune status of patients. Drinking history and duration of ventilator use are independent risk factors for postoperative complications of thoracoscopy-assisted esophagectomy, and high PNI is a protective factor for postoperative complications.