Abstract：Objective：To observe the clinical effect of Bufei Pingchuan tang combined with modern medicine therapy for asthma- chronic obstructive pulmonary disease overlap syndrome(ACOS). Methods： A total of 84 cases of ACOS patients were divided into the control group and the treatment group according to their random number table method，with 42 cases in each group. The control group was treated with inhalation with salmeterol/ticasone combined with tiotropium， and the treatment group was additionally treated with Bufei Pingchuan tang based on the treatment of the control group. Both groups were treated for eight weeks. The clinical effects in the two groups were compared. Before and after treatment，the changes in scores of Asthma Control Test(ACT) and COPD Assessment Test(CAT)， and lung function indexes including forced expiratory volume in one second(FEV1) and FEV1 to forced vital capacity(FEV1/FVC) ratio in the two groups were compared. Results：The total effective rate of clinical effect was 95.24% in the treatment group and 80.95% in the control group，the difference being significant(P＜0.05). After treatment， ACT scores in the two groups were increased when compared with those before treatment，and CAT were decreased，differences being significant(P＜0.05). After treatment，ACT score in the treatment group was higher than that in the control group，and CAT score was lower，differences being significant(P＜0.05). After treatment， the values of FEV1 and FEV1/FVC in the two groups were increased when compared with those before treatment(P＜0.05)， and the two values in the treatment group were higher than those in the control group， differences being significant(P＜0.05). Conclusion：Bufei Pingchuan tang combined with modern medicine therapy has a definite curative effect in treating ACOS，and can effectively improve clinical symptoms and lung function.