Objective To investigate the risk factors of postoperative pulmonary complications (PPC) after major abdominal surgery. Methods Clinical data were collected from 1 538 patients who underwent major abdominal surgery from January 2016 to June 2019 for retrospective analysis. Logistic regression analyses were performed to screen out the independent risk factors for PPC from relevant variables in demographical information, laboratory indicators and surgical information, to establish and verify a simple prediction model. Results Among the 1 538 patients, there were 332 (21.6%) patients at ≥ grade 3 (major pulmonary complications), and 1 206 (78.4%) patients at grade ≤2 (without pulmonary complications). Univariate analysis confirmed that sex, age, American Society of Anesthesiologists (ASA) grade, stroke history, preoperative pulse oxygen saturation (SpO2), emergency operation, upper abdominal surgery, operation duration; intraoperative infusion volume, plasma transfusion, blood loss, and urine volume; levels of platelet, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and troponin were significant factors (P<0.05). Multivariate logistic regression analysis showed that ASA grade, stroke history, SpO2≤97%, emergency surgery, and upper abdominal surgery were the independent risks of PPC in patients with major abdominal surgery. A risk scoring system was established through assigning values to each factor according to the β value. A receiver operating characteristic curve (ROC) was plotted and the area under the cure curve (AUC) was calculated. The result was 0.60 (95%CI 0.57, 0.62). Conclusions ASA grade, stroke history, SpO2≤97%, emergency surgery, and upper abdominal surgery are the independent risk factors for PPC in patients after major abdominal surgery. The risk scoring system established in this study is helpful to predict the occurrence of PPC and needs further improvement.