Abstract: ［Abstract］ Objective〖HTSS〗〓To compare the clinical effect of theophylline and doxophylline on moderate stable chronic obstructive pulmonary disease （COPD）.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓A total of 107 patients with COPD in stable period were randomly divided into theophylline group with 56 cases and doxophylline group with 51 cases. Theophylline group was administered theophylline sustained release 400 mg once daily and Doxophylline group was administered doxophylline 400 mg twice a day orally. The forced vital capacity(FVC), forced expiratory volume in 1 second(FEV1) and the ratio of FEV1 and FVC were recorded after 14 days of the drug treatment to observe the pulmonary function. COPD assessment test  was evaluated and adverse reactions were monitored of the two groups after 14 days of therapy.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓FVC, FEV1 and FEV1/FVC were improved after treatment in both groups, and that the improvement was statistically significant as compared to the pretreatment values in each group(P＜005). But the improvements in the theophylline and the doxofylline groups were not significantly different from each other(P＞005). The score of COPD assessment test was decreased significantly after the drug treatment in both groups(P＜005). The rate of adverse reactions was 9.8% during the treatment of doxofylline, which is significantly lower than 25.0% during the treatment of theophylline(P＜005).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓It is concluded that both theophylline and doxofylline can improve the quality of life and lung function of patients of COPD, and doxofylline has a better clinical effect and safety.

Key words: pulmonary disease, chronic obstructive, theophylline, treatment outcome