Obesity is one of the characteristics of type 2 diabetes mellitus. Most of the obese diabetes patients are combined with dyslipidemia or hypertension. The clustering of diabetes, obesity, hypertension and dyslipidemia increases the risk of cardiovascular events for patients. GLP-1 (glucagon like peptide-1) is a kind of incretin discovered in recent years. It was reported that beside its hypoglycemic and losing weight effects, activator of GLP-1 receptor could decrease blood pressure and improve lipid metabolism. Therefore, activation of GLP-1 receptor may become a new comprehensive treatment strategies for improving glucose and lipid metabolism, blood pressure level and cardiovascular complication. But, it is lack of evidence-based medicine proof on the relationship between GLP-1 and blood pressure or serum lipid. So, investigators designed a prospective, randomized, open-label, active control study, and try to evaluate the effects of activator of GLP-1 receptor (liraglutide) on lowering blood pressure, improving vascular function and lipid metabolism in overweight or obese type 2 diabetic patients with masked hypertension.