To observe the curative effect of Huangqi Decoction added with Guizhi on allergic rhinitis of lung qi weak and cold pattern and to discuss its certain mechanism. Methods: A hundred and thirty-four patients with allergic rhinitis of lung qi weak and cold pattern in the hospital from January 2012 to June 2014 were included into the study and randomly divided into the control group and the observation group with 67 cases in each group. The patients of the control group received conventional triamcinolone acetonide nasal spray method once a day, while the patients in the observation group received the same conventional treatment methods as the control group and additionally took modified Huangqi Decoction added with Guizhi twice a day with 100 mL warm solution. All the patients received three courses of treatment, with 20 days for each course of treatment. Nasal symptom scores and T lymphocyte subsets level changes in peripheral blood of patients before and after the treatment were compared. Results: 1) The clinical total effective rate in the control group after treatment was73.68% and 90.79% in the observation group and the comparison of the two groups showed statistically significant differences (P<0.05). The observation group was better than the control group. The clinical symptom scores and clinical symptoms in both the two groups decreased after treatment and the downward trend in the observation group was more obvious. 2) CD4+, CD4+/CD8+ increased in the control group after treatment, but there were no statistically significant differences compared with that before the treatment (P>0.05). CD4+, CD4+/CD8+ increased in the treatment group after treatment, showing obvious statistically significant differences compared with that before the treatment (P<0.05); CD8+ in the two groups after treatment decreased compared with those before the treatment (P<0.05). The comparison between the treatment group and control group in CD4+, CD8+, CD4+/CD8+ after treatment showed statistic differences (P<0.05) and the improvement of the treatment group were better than that of the control group. 3) The expressions of IgA, IgG and IgM of the patients in the two groups after treatment were significantly reduced (P<0.05)and the expression level of IgA, IgG, IgM in the observation group were lower than that in the control group (P<0.05). Conclusion: Huangqi Decoction added with Guizhi may improve allergic rhinitis symptoms significantly in lung qi weak and cold type and its mechanism may related to the improvement of patients’immunity.