Objective To investigate the effect of perioperative respiratory guidance on lung function and complications in patients undergoing thoracoscopic lung cancer resection. Methods This study selected 80 perioperative patients undergoing thoracoscopic lung cancer resection from February 2021 to July 2024. The study subjects were divided into a control group and an observation group using a random number table method, with 40 cases in each group. The control group received routine nursing interventions, while the observation group received respiratory guidance on the basis of the control group. Lung function indicators after invervention, postoperative recovery indicators, and incidence of complications were compared between the two groups. Results Before intervention, there was no significant difference in pulmonary function indexes [forced expiratory volume in 1 s （FEV₁）, vital capacity （VC）, and forced vital capacity （FVC）] between the two groups. After intervention, the lung function indicators of the observation group were significantly higher than those of the control group （P<0.05）. The observation group had significantly lower postoperative exhaust time and initial out-of-bed time than the control group （P<0.05）. The incidence of complications in the observation group was only 7.50%, lower than 32.50% in the control group （χ²=7.813,P<0.05）. Conclusion Respiratory guidance during the perioperative period for patients undergoing thoracoscopic lung cancer resection can improve their lung function while reducing the incidence of complications, which has clinical significance.