Abstract: OBJECTIVE To investigate the distribution of pathogens causing postoperative pulmonary infections in patients with esophagus cancer and analyze the influence on lung function. METHODS A total of 41 esophagus cancer patients with postoperative pulmonary infections who were treated in the hospital from Jan 2015 to Jan 2017 were chosen as the infection group, 50 esophagus cancer patients who did not have postoperative pulmonary infections were chosen as the non-infection group, and 60 healthy people who received physical examination were set as the control group.The sputum specimens that were obtained from the patients with the infections were cultured, and the isolated pathogens were identified.The postoperative length of hospital stay and mortality rate were compared between the infection group and the non-infection group, and the lung function and levels of serum cytokines were observed and compared among the three groups of participants. RESULTS The postoperative length of hospital stay of the infection group was (18.9±3.1) days, significantly longer than the non-infection group(P＜0.01). The mortality rate of the infection group was significantly higher than that of the non-infection group during the hospital stay (P<0.05). Totally 60 strains of pathogenic bacteria were isolated from the 41 patients with infections, of which 35 (58.33%) were gram-negative bacteria, 22 (36.67%) were gram-positive bacteria, and 3 (5.00%) were fungi.The lung function indexes FVC, FEV1, FEV1% and FEV1/FVC were significantly lower in the infection group than in the non-infection group and the control group(P＜0.05).The levels of peripheral blood CRP, TNF-α, IL-6 and IL-1β of the infection group were remarkably higher than that of the non-infection group and the control group(P＜0.05). CONCLUSION The gram-negative bacteria are dominant among the pathogens causing the postoperative pulmonary infections in the patients with esophagus cancer, the infections may extend the length of hospital stay, lead to the increase of mortality rate and result in the deterioration of lung function as well as systemic inflammatory reactions.