To explore the effect of Bailing Capsule（百令胶囊）combined with aminophylline in the treatment of chronic obstructive pulmonary（COPD）in stable phase and the effect on the expression of Kelch like epichlorohydrin related protein-1（Keap1）-nuclear transcription factor erythroid 2p45（Nrf2）-antioxidant response element（ARE）signaling pathway，so as to provide effective reference for clinical medication.

A prospective randomized controlled study of 112 patients with stable COPD in the hospital from February 2020 to March 2023 were selected and divided into combination group（56 cases）and control group（56 cases）by random number table.Both groups were given conventional treatment.On this basis，the control group was given aminophylline，and the combination group was given Bailing Capsule combined with aminophylline，both of which were treated for 3 months.The efficacy，the 6-min walking distance，changes in dyspnea index（TDI）and lung function［expiratory volume in the first second（FEV₁），forced vital capacity（FVC），FEV₁/FVC］，serum inflammatory factor indicators［tumor necrosis factor-α（TNF-α），interleukin-6（IL-6），high-sensitivity C-reactive protein（hs-CRP）］，immune function indexes（CD3⁺，CD4⁺，CD4⁺/CD8⁺）and the expression of Keap1-Nrf2-ARE signal pathway before and after treatment of the two groups were compared.

（1）Efficacy and symptom improvement：The total effective rate of the combination group was 91.07%（51/56），which was higher than that of the control group（75.00%，42/56）.After treatment，the TDI was higher than that of the control group（P<0.05）.（2）Sports endurance and lung function：After treatment，the 6-min walking distance，the levels of FEV₁，FVC and FEV₁/FVC in both groups increased compared to those before treatment，and the indexes of the combination group were higher than those of the control group（P<0.05）.（3）Inflammatory response：Compared with those before treatment，after treatment，the serum levels of inflammatory factors such as TNF-α，IL-6 and hs-CRP were significantly reduced，with a higher decrease in the combination group（P<0.05）.（4）Immune function：After treatment，the levels of CD3⁺，CD4⁺and CD4⁺/CD8⁺in the combination group were higher than those in the control group（P<0.05）.（5）Keap1-Nrf2-ARE signaling pathway：After treatment，the expression levels of Keap1，Nrf2 and ARE proteins increased in both groups，with the combination group showing a more significant increase（P<0.05）.

The combination of Bailing Capsule and aminophylline has a significant clinical effect in the treatment of stable COPD，which can effectively promote the improvement of patients’symptoms，improve lung function and exercise endurance，while reducing the body´s inflammatory response，improving immune function and up-regulating the expression of Keap1-Nrf2-ARE signaling pathway.