To discuss the influence of Buzhong Yiqi decoction on lung function in patients with acute exacerbation COPD.Methods:74 patients with acute exacerbation COPD were randomly divided into the observation group(n=37) and the control group(n=37),the control group were treated with ambroxol inhalation, the observation group were treated with Buzhong Yiqi decoction in addition to ambroxol inhalation. Comprehensive efficacy and the lung function were compared between the two groups. Results: The significant efficacy and the overall efficacy of the observation group were significantly higher than the control group(P<0.05);FEV1 and FVC in the observation group were significantly improved after the treatment(P<0.05 or P<0.01),but no significant improvement of FEV1/FVC(P>0.05), or three lung function indicators were observed after treatment (P>0.05),but FEV1 and FVC in the observation group were significantly higher than the control group after the treatment(P<0.05),no significantly difference in the incidence of adverse reactions between the two groups(P>0.05). Conclusion: Buzhong Yiqi decoction has definite treatment effects in patients with acute exacerbation COPD,and can effectively improve patients' lung function, its efficacy and safety is recommendable for clinical application..