Objective To assess the effects of physiotherapy on pulmonary function in COPD patients with lung cancer after lobectomy or pneumonectomy. Methods Fifty-five COPD patients with lung cancer undergoing lobectomy or pneumonectomy from January 2005 to May 2014 were recruited in the study. They were divided into group A received comprehensive physiotherapy before surgery and group B without comprehensive physiotherapy before surgery. The changes of lung function and tolerance were compared before physiotherapy (T1 time point) and after physiotherapy (T2 time point) in the group A, and between two groups before lung resection (T2 time point) and after lung resection (T3 time point). Results In group A, the forced expiratory volume in one second (FEV1), vital capacity (VC), peak expiratory flow at 50% of vital capacity (FEF50) and FEF25 increased significantly respectively by 16.96%, 14.75%, 20.69% and 13.79% compared with those before physiotherapy. Meanwhile, six-minutes walking distance (6MWD) achieved a significant improvement. After resection of lung, FEV1 and VC appeared to reduce, and pulmonary small airway function, tolerance, and clinical features deteriorated significantly. The differences between T2 and T1 in FEV1, FEF50 and FEF25 in the patients with FEV1%pred ≥80% and 50%-80% were similar with those in the patients with FEV1%pred<50%. The differences between T2 and T3 in FEF50 and FEF25 in the patients with FEV1%pred≥80% and 50%-80% were higher than those with FEV1%pred<50%. For the patients with lobectomy, FEV1 and VC in the group B were lower than those in the group A (FEV1: 10.24% vs. 22.44%; VC: 10.13% vs. 20.87%). For the patients with pulmonary resection, FEV1 and VC had little differences (FEV1: 36.33% vs. 36.78%; VC: 37.23% vs. 38.98%). Conclusion Physiotherapy is very important for the preoperative treatment and postoperative nursing of COPD patients with primary lung cancer.