Objective To evaluate the clinical efficacy and safety of Kuanxionglifei Decoction combined with Sanziyangqin Decoction (KXLFD-SZYQD) in treating acute exacerbation of chronic obstructive pulmonary disease (AECOPD) with turbid phlegm obstructing lung syndrome, and to observe its effect on the lung function and routine blood tests. Methods Ninety patients meeting the diagnosis criteria were randomly divided into three groups. Thirty cases in KXLFD-SZYQD group were treated with western medicine and KXLFD-SZYQD, thirty cases in Kuanxionglifei Decoction (KXLFD) group were treated with KXLFD and western medicine, and thirty cases administered with western medicine alone were taken as controls. The therapeutic course was 7 d. The clinical therapeutic effects, accumulated scores of symptoms, pulmonary function and routine blood test were observed before and after treatment. Results (1) The total effective rates of KXLFD-SZYQD group, KXLFD group and control group were 93.3%(28/30), 80.0%(24/30) and 66.7%(20/30), respectively, with significant difference found between KXLFD-SZYQD group and control group (P=0.01). (2) The accumulated scores of symptoms showed that the improvement in KXLFD-SZYQD group was significantly greater than those in the other two groups (P=0.018, P=0.000), and the improvement of KXLFD group was significantly greater than that of the control group (P=0.027). (3) Compared with control group, KXLFD-SZYQD group also had significantly improved FEV₁%, FEV₁/FVC%, WBC and NEUT% (P=0.003, P=0.000, P=0.001,and P=0.003, respectively), and compared with KXLFD group, the improvement in KXLFD group was greater than that in the control group, but without significant difference (P=0.032, 0.037, 0.037,and 0.034, respectively). (4) The vital signs of the three groups were stable during the treatment, and there were no damage to the heart, liver or kidney and no other serious complications. Conclusion KXLFD-SZYQD combined with western medicine treatment can decrease WBC count and neutrophil percent, improve lung function and the clinical condition of AECOPD patients with turbid phlegm obstructing lung syndrome.