The invention belongs to the field of biochemistry and molecular biology, and particularly relates to an application of aucubin in preparation of a medicine for treating type 2 diabetes mellitus. Compared with a model group, an aucubin low-dose group, an aucubin medium-dose group and an aucubin high-dose group (1, 5 and 10 mg/kg) can improve the weight and fasting blood-glucose of type 2 diabetesmice, reduce the IL-6 and IL-1 beta levels in model serum and inhibit phosphorylation of IkappaB and NF-kappaB-p65 in an NF-kappaB signal path in pancreas. The application shows that aucubin can correct the inflammatory state of type 2 diabetes and improve the symptoms of type 2 diabetes and can serve as a therapeutic drug to be applied to treatment of type 2 diabetes mellitus.