To investigate the effect of Xiaoqinglong Decoction on T lymphocyte subsets in acute exacerbation of chronic bronchitis.Methods:The clinical data of 118 patients with acute exacerbation of chronic bronchitis were retrospectively analyzed.The patients were divided into control group(n=59)and study group(n=59)according to treatment methods.Both groups were treated with conventional western medicine, and study group received Xiaoqinglong Decoction in addition.Lung function, T lymphocyte subsets, inflammatory factors, SF-36 and improvement time of related symptoms were observed and compared between the two groups before and after treatment.Results:After 2 weeks of treatment, the improvement effect of FVC、FEV1、FEV1/FVC、CD3+、CD4+、CD25+、CD95+、CD3+/CD25+、CD8+/CD28+in the study group were better than those in the control group.The down-regulation of IL-8,TNF-α,IL-6,IL-17,CD19+ and the improvement of various dimension of life quality score, heat regression time, expectoration improvement time,cough improvement time, dry and wet rales improvement time in the study group were much better than those in the control group(P<0.05).Conclusion:Xiaoqinglong Decoction can alleviate the clinical symptoms of acute exacerbation of chronic bronchitis and improve the quality of life by inhibiting inflammatory reaction, improving lung function and immune function.