Objective：To assess the safety and efficiency of metformin and glyburide in gestational diabetes mellitus by comparing with insulin. Methods：Relevant 16 randomized controlled trials published before December，2013 were searched from PubMed，EMBASE，the Cochrane Central Register of Controlled Trials（CENTRAL），and Chinese biomedicine（CBM） literature database. The safety and efficiency between metformin and glyburide was assessed using direct and indirect results through R 2.15.2. Results：A total of 2 665 participants were identified in this Meta analysis. There were more macrosomia in glyburide group and in insulin group（OR=3.299，95%CI=1.649 to 6.600，P=0.001），more macrosomia in glyburide group than in metformin group（OR=0.234，95%CI=0.061 to 0.893，P=0.033），however there was no difference in macrosomia between metformin group than insulin group（P=0.198）. Maternal weight gain was lower in metformin group than in insulin group（SMD=-0.539，95%CI=-0.716 to -0.362，P=0.000）. Gestational age was smaller in metformin group than insulin group（SMD=-0.142，95%CI=-0.246 to -0.039，P=0.007）. Conclusion：Metformin can better control blood glucose and maternal weight gain and lower glycosylated hemoglobin level without increasing maternal hypoglycaemia，but it may significantly shorten gestational age. Incidence of macrosomia is higher in glyburide group.