This study compared the efficacy and safety of tiotropium bromide inhalation powder (spiriva) and doxofylline oral tablet (doxofylline) in the treatment of chronic obstructive pulmonary disease (COPD).A multi-center,randomized,double-blind,double-dummy,parallel-controlled study involved 127 eligible stable moderate to severe COPD patients treated with inhaled tiotropium dry powder (18 μg/day) or oral doxofylline tablets (0.2 g/time,2 times a day) for 12 and 24 weeks.Before and after treatment for 12 weeks and 24 weeks,respectively,pulmonary function,6-min walking distance and dyspnea index were recorded.The results showed that in both tiotropium group and doxofylline groups,after 12-week treatment,FEV1,FEV1/FVC％ and 6-min walk distance were significantly higher than those before the medication,while dyspnea index decreased as compared with that before treatment.After 24-week treatment,a slight improvement in the measures was observed as compared with that of 12-weeks treatment,but the difference was not statistically significant.With both 12-week and 24-week treatment,the effect of tiotropium was slightly better than that of doxofylline tablets,with the difference being statistically insignificant.The major adverse events in the tiotropium group and doxofylline group were observed in 9 cases (9.9％) and 12 cases (12.9％),respectively,and no statistically significant difference was found between them.We are led to conclude that both tiotropium at 18 μg a day and doxofylline tablets at 0.2 g/day (two times a day) are effective and safe for the treatment of COPD.