Alpha-glucosidase (EC 3.2.1.20) is a carbohydase that catalyzes the liberation of -glucose from the non reducing end of the diet carbohydrate. In diabetic patient inhibiton of these enzymes causes the restraint of glucose absorption and decreas the postpradial hyperglycemia. The purpose of this research is to study the antihyperglycemic activity of mahkota dewa [Phaleria macrocarpa (Scheff.) Boerl.] leaf extracts by inhibiton test to alpha glucosidase enzyme. This research was conducted in three steps fractination and extraction samples with methanol ethyl acetate n-butanol and water followed by phytochemistry screening and alpha-glucodidase inhibition test. The alpha-glucosidase inhibition test was performed by using alpha-glucosidase enzyme and p-nitrophenyl alpha D-glucopyranoside as a substrate. The result of phytochemistry sceening showed that Mahkota dewa leaves contain class of phenolics thanins flavonoids alcaloids and carbohydrates. The result of alpha-glucoside inhibition percentage at 50 ppm for old leaves methanol extract which is 14.25% and 10.97% for young leaves and for old leaves boiled water extract is 10.32% and 6.58% for young leaves. For n-butanol fraction extract inhibition activity of young leaf extract (14.26%) is higher than old leaf extract (9.49%).