Objective To investigate the effects of penehyclidine on respiratory mechanics after tracheal intubation in patients with chronic obstructive pulmonary disease. Methods Sixty-six patients with chronic obstructive pulmonary disease were divided randomely into two groups. Group Ⅰ (penehyclidine group, 33 cases) was intravenously injected 1 mg of penehyclidine before intubation, group Ⅱ (control group, 33 cases)was not given bronchodilator. Lung-chest walt compliance, airway pressure, and resistance were measured at 1 h,4 h,and 6 h after tracheal intubation. Results Patients in group Ⅰ had significantly both lower airway pressure and resistance and higher lung-chest wall compliance than group Ⅱ (P < 0. 05). Conclusion Penehyclidine produces higher lung-chest wall compliance and lower airway pressure and resistance in patients with chronic obstructive pulmonary disease.