Objective To explore the predictive value of cardiopulmonary exercise test (CPET) combined with clinical indexes in the postoperative complications. Methods The clinical data and CPET data (including lung function) of patients undergoing radical esophagectomy in Xuzhou Central Hospital from January 2018 to March 2022 were collected. Univariate analysis and multivariate logistic regression analysis were used to analyze the meaningful evaluation index for the occurrence of postoperative complications. Results A total of 77 patients with esophageal cancer were included, including 59 (76.6%) males and 18 (23.4%) females aged 47-80 years. There were 42 (54.5%) patients in the non-complication group and 35 (45.5%) patients in the complication group. Univariate analysis results showed that the occurrence of postoperative complications was significantly correlated with age, body mass index (BMI), smoking index, tumor stage, the length of postoperative hospital stay, peak work rate (WRpeak), peak kilogram oxygen uptake (VO2peak/kg), the ventilatory equivalent for carbon dioxide slope (VE/VCO2 slope), forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) and maximum expiratory flow rate (MMEF) (P<0.05). The results of multivariate logistic regression analysis showed that BMI [OR=1.35, 95%CI (1.03, 1.77), P=0.031], peakVO2/kg [OR=0.64, 95%CI (0.45, 0.93), P=0.018], oxygen uptake-anaerobic threshold (ATVO2) [OR=0.66, 95%CI (0.44, 0.98), P=0.044] and VE/VCO2 slope [OR=1.49, 95%CI (1.10, 2.02), P=0.011] were the related indexes of complications after radical resection of esophageal cancer. The sensitivity of BMI, VO2peak/kg, ATVO2/kg and VE/VCO2 slope in predicting postoperative complications was 82.10%, and the specificity was 87.44%, 95%CI (0.744, 0.955). Conclusion BMI, VO2peak/kg, ATVO2/kg and VE/VCO2 slope can be used as predictors for postoperative complications of esophageal cancer.