To explore the effect of Shengyang Yiwei decoction on preventing recurrence of chronic bronchitis and on immune function.Methods:A total of 98 patients with recurrent acute episodes of chronic bronchitis admitted to the National Hospital of Guangxi Zhuang Autonomous Region from March 2017 to March 2019 were selected and randomly divided into control group (n=49) and observation group (n=49).The control group was treated with routine treatment,and the study group was treated with Shengyang Yiwei decoction on the basis of the control group,both for 4 weeks.The changes of immune function,frequency of recurrence,pulmonary function,inflammatory factors and clinical efficacy were observed before and after treatment.Results:The total effective rate of the observation group was 89.79%,which was higher than that of the control group (77.55%),and the difference was statistically significant (P<0.05).After treatment,inflammatory factors,CD8+ and oxygenation index (OI) decreased in both groups(P<0.05),while CD3+,CD4+,CD4+/CD8+,arterial alveolar oxygen partial pressure ratio (a/A),forced expiratory volume in the first second (FEV1),forced vital capacity (FVC) and FEV1/FVC were all increased,the observation group were significantly better than those in the control group (P<0.05).There was no significant difference in the frequency of acute attack,the use of antibiotics,TCM symptom score,SF-36,complement C3,C4,immunoglobulin A (IgA),IgG and IgM in the control group(P>0.05).The improvement of the above-mentioned indexes in the observation group was better than that in the control group(P<0.05).Conclusion:Shengyang Yiwei decoction can improve the clinical symptoms of chronic bronchitis,and its mechanism may be related to the improvement of immune function.