Objective To evaluate the effect of tiotropium using in Stable Chronic Obstructive Pulmonary Diaease(COPD) through observing the changing of patients' lung function before and after using tiotropium.Methods Dividing 60 patients with stable COPD into 2 groups(experimental group and control group) randomly,30 patients as the experimental group inhaled tiotropium 18 μg once every morning;30 patients as the control group took orally Theo-Dur 0.1g each time,twice a day for 4 weeks.Then testing the changing of pa...