To study the curative effect of Maxing Shigan Decoction in the treatment of allergic rhinitis based on “simultaneous treatment of lung and nose” and its mechanism.Methods:Eighty-six cases with allergic rhinitis treated in the department of ENT of the hospital from August 2015 to February 2017 were selected and randomly divided into observation group and control group, with 43 patients in each group. Patients in the control group were given Loratadine tablets, while patients in the observation group were additionally taken Maxing Shigan decoction. Symptoms score and efficacy index were observed and recorded, and pulmonary function test of pulmonary airway function, including PEF%, FEF25%, FEF50%, FEF75% and MMEF75/25% serum immunoglobulin IgE and expression of T lymphocyte subsets CD3+, CD4+, CD8+ were detected and recorded.Results:1) There was no significant difference in symptom scores between the two groups before the treatment (P>0.05); the scores were lower than that before the treatment in both the two groups (P<0.05); the observation group was lower than the control group (P<0.05). 2) PEF%, FEF25%, FEF50%, FEF75% and MMEF75/25% were higher after the treatment (P<0.05); the observation group was better than the control group (P<0.05). 3) T lymphocyte subsets CD3+, CD4+, CD8+ (P<0.05), increased after the treatment; the percentage of CD4+/CD8+ decreased (P<0.05); CD3+, CD4+, CD8+ in the observation group increased more greatly (P<0.05), and IgE and CD4+/CD8+ were lower than those of the control group (P<0.05).Conclusion:Maxing Shigan Decoction in treating allergic rhinitis patients based on simultaneous treatment of lung and nose may improve symptoms like sneezing, running nose and others and enhance pulmonary airway function and its therapeutic mechanism may be related to the down-regulation of IgE and relief to the disorder of the expression level of T lymphocytes subsets.