Objective To systematically evaluate the curative effect of Xiaochaihu Decoction on diabetes mellitus by Meta-analysis. Methods Chinese National Knowledge Infrastructure(CNKI) and WanFang database were retrieve by computers. A randomized controlled trial of Xiaochaihu Decoction in the treatment of diabetes mellitus was reviewed and collected. From January 2009 to March 2019, the collected literature was chosen and message extracted the effective indexes. The data were analyzed by Revman5.3 software. Results A total of 726 patients were included. The results of Meta-analysis showed that the clinical efficacy of Xiaochaihu Decoction in the treatment of diabetes mellitus was significantly better than that of the control group, and the difference was statistically significant[OR=4.68，95%CI(2.98，7.33)]. In the treatment group, fasting blood glucose (MD=－1.14，P<0.01), postprandial 2 hour glucose (MD=－1.88, P<0.01), glycosylated hemoglobin (MD= －1.05, P<0.01) and cholesterol(MD=－1.29， P<0.01) were decreased.However there was no significant difference between the two groups in cholesterol (MD=－2.26， P=0.17). Conclusion Xiaochaihu Decoction can improve the clinical symptoms of diabetic patientsand effectively reduce the blood sugar.