To evaluate the value of the improved POSSUM scoring system combined with the Clavien-Dindo classification in predicting the incidence of severe complications after thoracoscopic lung surgery and provide quantitative basis for clinical decision-making and improvement of preoperative physiological state of patients are the objectives of this study. The POSSUM scoring system was improved, the original indicators with less impact on surgery were removed, and the new indicators with greater influence were included. A new scoring system was established, and the fourth was selected from Hebei Medical University from January 2016 to December 2016. Three hundred fifteen patients underwent thoracoscopic lung surgery in hospital thoracic surgery. Summarizing their preoperative and intraoperative data and using the modified POSSUM POSSUM score, graded by Clavien-Dindo, set nonserious complications as class I group and II similar to V level as serious complications. The number of complications predicted by POSSUM and modified POSSUM and the number of actual serious complications were compared, and the prediction rates of the two groups were compared. A total of 167 complications occurred in 315 patients, and the number of complications was 44.1% (139/315). All patients had no death record within 30 days after surgery. Using the Clavien-Dindo classification, grade I, II, III, IV, and above complications accounted for 22.5%, 11.1%, 9.8%, and 0.6%, respectively. Sixty-eight cases of serious complications accounted for 21.6%, and 71 cases of nonserious complications accounted for 22.5%. The prediction equation of the improved POSSUM scoring system is ln(R/1 - R) = - 11.727 + (0.339 x PS) + (0.304 x OS), where R is the incidence of postoperative complications. POSSUM and the improved scoring system have predictive effects on postoperative complications, and the improved POSSUM scoring system has better predictive value than the original score. The Clavien-Dindo grading system combined with a modified POSSUM score can accurately predict the incidence of serious complications after thoracoscopic lung surgery. The sensitivity and specificity of the modified POSSUM score were higher than the POSSUM score, and the prediction of complications after VATS lung surgery was more accurate.