The aqueous extract from the fruit body of Lentinus edodes was evaluated for inhibitory activities against $alpha$-glucosidase isolated from Spargue-Dawley male rats. A aqueous extract of Lentinus edodes exhibited 13.8% inhibitory activity on using 2 mM p-nitrophenyl $alpha$-D-glucopyranoside as a substrate ($IC_{50}$ 75.3 mg/ml). The aqueous extract of Lentinus edodes inhibition type on $alpha$-glucosidase was determined to be competitive inhibition. When it was oral administered to increase of blood glucose levels after STZ-induced in a dose dependent dietary. These results suggest that aqueous extract of Lentinus edodes effect a metabolism of intestine, and thereby reducing the increase of blood glucose after STZ-induced.