Abstract： Objective： To observe the curative effect of bi-level positive airway pressure ventilation mode（ST mode）combined with Bailing Capsules on acute exacerbation of chronic obstructive pulmonary disease（AECOPD）. Methods： A total of 102 cases of AECOPD patients admitted to the Department of Respiratory and Critical Care Medicine at Taizhou Central Hospital from September 2021 to June 2024 were selected and divided into the control group and the combination group according to the random number table method， with 51 cases in each group. The control group received conventional intervention，anti-infection treatment，and bi-level positive airway pressure ventilation， and the combination group received Bailing Capsules based on the treatment of the control group. Clinical indicators， blood gas analysis indicators [arterial partial pressure of oxygen（PaO2），fraction of inspired oxygen（FiO2），arterial partial pressure of carbon dioxide（PaCO2）， oxygenation index（OI）]， levels of inflammatory factors [interleukin-6 （IL-6），serum amyloid A（SAA），erythrocyte sedimentation rate（ESR）]，and immune function indicators [cluster of differentiation 3（CD3+），cluster of differentiation 19（CD19+），natural killer cells（NK）] were compared between the two groups. Results：The duration of cough，chest tightness，wheezing，abnormal heart rate，and hospital stay in the combination group was shorter than that in the control group（P＜0.05）. After treatment，the values of PaO2 and OI in the two groups were increased when compared with those before treatment （P＜0.05）， and PaCO2 values were decreased when compared with those before treatment（P＜0.05）. The values of PaO2 and OI in the combination group were higher than those in the control group（P＜0.05），and PaCO2 value was lower than that in the control group（P＜ 0.05）. After treatment，the levels of IL-6，SAA，and ESR in the two groups were reduced when compared with those before treatment（P＜0.05），with the combination group showing lower levels than the control group（P＜0.05）. After treatment， the values of CD3+ ， NK， and CD19+ in the two groups were increased when compared with those before treatment （P＜0.05）， with the combination group showing higher values than the control group （P＜0.05）. Conclusion：Bi-level positive airway pressure ventilation mode combined with Bailing Capsules can improve immune function，reduce airway inflammation，and enhance oxygen uptake capacity in AECOPD patients.