Objective:Evidence Based Medicine (EBM) is used to do systematic reviews on Shegan Mahuang tang (Ephedra decoction) controlling cough variant asthma (CVA) in children. Method:Data retrieval is done on the websites such as cnki, cqvip, wanfangdata and offline professional magazines. Result:Ninty-four pieces of literatures are attained and 7 pieces accord with the inclusive criteria. Jadad Criteria is adopted to assess every literature's Methodological quality, all of which are low quality ones. 470 cases are obtained. OR=2.99, 95% CI of 1.90 to 4.71, test for overall effect:Z=4.71(P<0.000 01). Therefore, the difference is statistically significant. Conclusion:The existed clinical evidences shows, Shegan Mahuang tang is effecitve to control cough variant asthma (CVA) in children. However, randonmized control clinical trials are subsumed by systematic reviews belong to low quality ones, so Shegan Mahuang tang's therapeutic effect need to be further examined by a large scale of high quality of clinical trials.