To observe the curative effects of Shegan Mahuang Decoction on treating cough variant asthma and its intervention effect on immune system.Methods:A total of 80 children with cough variant asthma admitted in the pneumology department in Affiliated Hospital of Xinyang Vocational and Technical College from January 2014 to February 2016 were included in the research,and were randomly divided into the observation group and the control group,with 40 cases in each group.The control group had oral administration of montelukast and inhaled albuterol aerosol,and the observation group had Shegan Mahuang Decoction 1 dose in a day on the basis of the treatment above.Both group accepted treatment for 12 weeks as a course.After treatment,asthma control test (C-ACT) score,number of acute onset of symptoms,pulmonary function and the change of immunological index of patients were compared between the two groups.Results:1) After treatment,C-ACT scores of the patients in the two groups were obviously improved,and the increasing scores of the observation group were more than those of the control group,and the differences were statistically significant (P<0.05); 2) after treatment,the number of acute onset of patients in the two groups decreased obviously,and the number of the observation group were less than that of the control group (P<0.05); 3) pulmonary function index improved significantly in both groups,and each index in the observation group was better than that of the control group (P<0.05); 4) the expression of CD8+ in the observation group was significantly lower than that of the control group (P<0.05),while the expression of CD4+ and CD4+/CD8+ in the observation group was higher than that of the control group (P<0.05).Conclusion:Shegan Mahuang Decoction can effectively relieve clinical symptoms of cough variant asthma,improve pulmonary function,and its mechanism may relate to the mediation of patients' immune system.