Objective To investigate the efficacy and side effects of acarbose and metformin in the treatment of type 2 diabetes mellitus. Methods 100 patients with type 2 diabetes mellitus's choice of the January 2015 to March 2017 in our hospital, the patients were randomly divided into two groups: the control group was treated with metformin, acarbose treatment in observation group; the two groups before and after treatment of blood glucose control, the adverse reaction condition of comprehensive observation, will be granted the relevant data recorded and analyzed. Results Patients with fasting blood glucose, 2 h postprandial blood glucose, glycosylated hemoglobin improvement than the control group, the difference was statistically significant (P<0.05); two groups of patients with adverse reaction rate comparison, the difference was not statistically significant. Conclusion Patients with type 2 diabetes choose acarbose treatment effect significantly, can effectively improve the patients fasting blood glucose, 2 h postprandial blood glucose, glycosylated hemoglobin, clinical symptoms of patients can be improved, low incidence of adverse reactions.