Objective,2,To investigate the effect of Bushen Yifei Decoction on airway mucus hypersecretion and lung function in patients with chronic obstructive pulmonary disease (COPD) in the stable stage.,Methods,2,Ninety patients with lung and kidney deficiency syndrome in the stable stage of COPD were randomly divided into the treatment group (,n,=45) and the control group (,n,=45). Both groups were administered with conventional medication (salmeterol xinafoate and fluticasone propionate powder for inhalation). The treatment group was additionally administered with Bushen Yifei Decoction, while the control group was administered with the placebo of traditional Chinese herbal medicine (TCHM). The course of treatment in both groups was 12 months. The annual frequency of acute exacerbations was observed, and changes in lung function-related indicators like FEV,1, FEV,1,/FVC% and FEV,1,%, as well as the changes in levels of MUC5AC, scores of sputum nature, and levels of peripheral blood neutrophil elastase (NE) were compared.,Results,2,①Finally 85 patients completed the trial, 43 cases in the treatment group and 42 cases in the control group. ②There was significant difference in the annual frequency of acute exacerbations between the two groups (,P,<,0.05). ③According to the inter-group comparisons after 6 months of treatment, the levels of FEV,1, FEV,1,/FVC% and FEV,1,% in the treatment group were significantly better than those in the control group (,P,<,0.05); According to the inter-group comparisons after 12 months of treatment, the levels of FEV,1, FEV,1,/FVC% and FEV,1,% in the treatment group were significantly better than those in the control group (,P,<,0.05). ④According to the inter-group comparisons after 6 months of treatment, the level of sputum MUC5AC, the score of sputum nature, and the level of peripheral blood NE in the treatment group were significantly lower than those in the control group (,P,<,0.05); According to the inter-group comparisons after 12 months of treatment, the level of sputum MUC5AC, the score of sputum nature, and the level of peripheral blood NE in the treatment group were significantly lower than those in the control group (,P,<,0.05). ⑤During the trial, there were no serious adverse events in both groups, and no abnormality in safety indicators were found.,Conclusion,2,Bushen Yifei Decoction combined with salmeterol xinafoate and fluticasone propionate powder for inhalation is effective and safe in treating chronic obstructive pulmonary disease in stable stage, which can significantly reduce patients’ annual acute exacerbation frequency, improve their lung function, sputum nature and airway mucus hypersecretion, and delay the decline of lung function.