Abstract: OBJECTIVE To explore the values of peripheral blood interleukin-33 (IL-33) and suppression of tumorigenicity 2 (ST2) in prediction of postoperative infections in lung cancer patients. METHODS Totally 221 lung cancer patients who received surgical procedures in First Affiliated Hospital of Jinzhou Medical University from May 2022 to May 2025 were recruited as the research subjects and were divided into the infection group with 53 cases and the no infection group with 168 cases according to the status of postoperative infections. The clinical data and the levels of postoperative peripheral blood IL-33 and ST2 were observed and compared between the two group. The risk factors for the postoperative infections in the lung cancer patients were analyzed by multivariate logistic regression model. The clinical efficiencies of the postoperative peripheral blood IL-33 and ST2 in prediction of postoperative infections were analyzed by means of receiver operating characteristic (ROC) curves. RESULTS The incidence of infections was 23.98% among the 221 patients. Totally 76 strains of pathogens were isolated from the 53 patients with infections, 53 (66.74%) of which were gram-negative bacteria, 21 (27.63%) were gram-positive bacteria, and 2 (2.63%) were fungi. The levels of peripheral blood IL-33 and ST were higher in the infection group than in the no infection group after the surgery for 1 and 3 days(P＜0.05). Logistic regression model analysis showed that age, complication with diabetes mellitus and operation duration were the risk factors for the postoperative infections in the lung cancer patients(P＜0.05). ROC curve analysis indicated that the sensitivities of IL-33, ST2 and the combination of the two indicators in prediction of the postoperative infections were 52.83%, 62.26% and 90.57%,respectively; the AUCs were 0.709, 0.761 and 0.842, respectively; the AUC of the combined detection of the two indicators was higher than that of the single detection in prediction of the postoperative infections in the lung cancer patients(P＜0.05). CONCLUSION The patients with postoperative infections show remarkable rise of levels of peripheral blood IL-33 and ST2 in early stage, and the combined detection of the two indicators is superior to the single detection in predictive efficiency for the postoperative infections.