Objective · To explore the risk factors of postoperative complications after radical gastrectomy + D2 lymphadenectomy and establish a predictive nomogram model. Methods · From July 2016 to June 2019, 1 705 patients who received radical gastrectomy + D2 lymphadenectomy in the Department of Gastrointestinal Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine were collected. According to Clavien-Dindo grading system, the postoperative complications were graded, and the risk factors of postoperative complications ≥grade Ⅱ were analyzed by χ2 test. Multivariate Logistic regression was used to analyze the independent risk factors of postoperative complications ≥grade Ⅱ. According to the selected independent risk factors, the nomogram model was established. For verification, above patients were used as the training set, and 612 patients undergoing the same operation in this department from July to December 2019 were used as the validation set. Results · A total of 416 (24.4%) gastric cancer patients had postoperative complications. Multivariate Logistic regression analysis showed that male (OR=1.507, P=0.002), age ≥60 years old (OR=1.962, P=0.001), maximum diameter of tumor ≥5 cm (OR=1.456, P=0.002) and total gastrectomy (OR=1.313, P=0.026) were independent risk factors for postoperative complications ≥ grade Ⅱ . Based on these independent risk factors, the nomogram was established and presented good discrimination and predictive consistency in training set and validation set. Conclusion · The nomogram based on these four independent risk factors has a good predictive performance in predicting postoperative complications after radical gastrectomy for gastric cancer, and has a certain clinical application and reference value.