To study and explore the clinical effect of the levofloxacin combined with Jiawei Qianjin Weijing Decoction in the treatment of chronic bronchitis with acute attack. Methods:Sixty patients with chronic bronchitis on acute exacerbation who were admitted and treated in department of respiratory medicine of our hospital from January 2015 to October 2016 were selected. By using single blind random method, all patients were randomly divided into control group and observation group, with 30 patients in each group. The patients in the control group were treated with levofloxacin, and the patients in the observation group were treated with Qianjin Weijing decoction on basis of control group. The two groups were compared in clinical total effective rate, symptoms remission time, pulmonary function indicators, peripheral monocyte T iymphocyte (Th17) percentage and the adverse effects rate. Results:The clinical total efficiency rate of the observation group was significantly higher than that of the control group (P<0.05); symptom remission time of the observation group was significantly shorter than that of the control group (P<0.05); pulmonary function indicators of both groups were improved (P<0.05), but the patients in the observation group were better than the patients in the control group (P<0.05); after treatment, the percentage of CD4+IL-17+T cells of observation group was （1.21±0.21）%, which was lower than that of the control group, and there were no significant differences between the groups during the treatment. Conclusion:Levofloxacin combined with Qianjin Weijing decoction in treating chronic bronchitis on acute exacerbation has significant clinical efficacy, and effectively promote the remission of symptoms, and improve the pulmonary ventilation function, and also ensure safety. Its mechanism of action may be related to the reduction of Th17 expression.