Abstract: Objective To observe and evaluate the effect of a deep breathing trainer during perioperative period on postoperative pulmonary complications in elderly patients with elective upper abdominal surgery. Methods From January to December 2017, 100 elderly patients with upper abdominal surgery in our hospital were selected and randomly divided into study group and control group, with 50 cases in each group. During the perioperative period(5 days before operation-7 days after operation), the control group was given routine surgical intervention, while on the basis of the control group, the study group received intensive intervention of respiratory function exercise with deep breathing trainer 5 days before operation to 7 days after operation(6 hours after operation). Clinical observation index included forced vital capacity(FVC), 1 s expiratory volume(FEV1), maximum deep inspiration volume(IC), partial pressure of oxygen(PaO₂), partial pressure of carbon dioxide(PaCO₂), blood oxygen saturation(SaO₂) at the time points of preoperative(5 d, 1 d) and postoperative(1 d, 4 d, 7 d). At the same time, the anesthesiologist used the improved bedside ultrasound lung examination protocol(BLUE) method to dynamic examination at beside, to observe whether there were pulmonary complications such as pulmonary insufficiency and pulmonary infection. Results Compared with control group, the levels of FVC, FEV1 and IC in the observation group were significantly increased, and the indexes of PaO₂, PaCO₂ and SaO₂ were significantly improved. The incidence rate of postoperative atelectasis and pulmonary infection in the observation group was significantly less than that of the control group, and the average length of stay was shorter. Conclusion The use of deep breathing trainer in elderly patients during the perioperative period can effectively improve the lung function, reduce the incidence of postoperative pulmonary complications, improve the quality of patient's life, and has great significance to promote rapid recovery.