ObjectiveTo evaluate the effect of perioperative nebulization of ipratropium bromide on preoperative pulmonary function and incidence of postoperative pulmonary complications as well as safety in chronic obstructive pulmonary disease (COPD) patients who underwent lung resection in thoracic surgery. MethodsDuring November 18, 2013 to August 12, 2015, 192 COPD patients with a necessity of selective surgical procedures of lobectomy or right bilobectomy or segmentectomy under general anaesthesia in 10 centers were 1 : 1 randomized to an ipratropium bromide group (96 patients) and a placebo group (96 patients), to compare the effect on preoperative pulmonary function and incidence of postoperative pulmonary complications. The average age of treated patients was 62.90±6.50 years, with 168 male patients and 22 female patients. Results The demographic and baseline characteristics were well-balanced between the two groups. The adjusted mean increase of forced expiratory volume in one second (FEV1) in the ipratropium bromide group was significantly higher than that in the placebo group (169.90±29.07 mL vs. 15.00±29.35 mL, P<0.05). The perioperative use of ipratropium bromide significantly decreased incidence of postoperative pneumonia (2.6% vs. 14.1%, P<0.05). There was no ipratropium bromide related adverse event (AE) observed in this trial. ConclusionThis trial indicates that perioperative nebulization of ipratropium bromide significantly improves preoperative lung function and reduces postoperative pneumonia in COPD patients undergoing lung resection in thoracic surgery, and has good safety profile.