Background Now lung volume reduction surgery (LVRS) has become one of the most effective methods for the management of some cases of severe chronic obstructive pulmonary disease (COPD). We evaluated the mid-term effects of LVRS on pulmonary function in patients with severe COPD. Methods Ten male patients with severe COPD aged 38-70 years underwent LVRS and their pulmonary function was assessed before, 3 months and 3 years after surgery. The spirometric and gas exchange parameters included residual volume, total lung capacity, inspiratory capacity, forced vital capacity, forced expiratory volume in one second, diffusion capacity for CO, and arterial blood gas. A 6-minute walk distance (6MWD) test was performed. Results As to preoperative assessment, most spirometric parameters and 6MWD were significantly improved after 3 months and slightly 3 years after LVRS. Gas exchange parameters were significantly improved 3 months after surgery, but returned to the preoperative levels after 3 years. Conclusions LVRS may significantly improve pulmonary function in patients with severe COPD indicating for LVRS. Mid-term pulmonary function 3 years after surgery can be decreased to the level at 3 months after surgery. Three years after LVRS, lung volume and pulmonary ventilation function can be significantly improved, but the improvement in gas exchange function was not significant.