To investigate the effect of compound FF16, compatibility of Rhodiola crenulata, Cordyceps militaris, and Rheum palmatum, on obesity, both the insulin resistant obese IRF mouse model induced by high fat diet and the spontaneous type 2 diabetes KKAy obese mouse model were used. The results showed that the body weights and the energy uptake were markedly reduced by compound FF16 in both IRF mice in dose-dependent manner and KKAy mice, respectively. Meanwhile, with the administration of FF16, the hypercholesterolemia and the hypertriglyceridemia were improved significantly in KKAy mice; and the levels of serum cholesterol and fatty index were decreased obviously, and the value of serum HDL-C was increased significantly in IRF mice, respectively. Moreover, the activity of a-glycosidase was inhibited by compound FF16 in vitro. In conclusion, FF16 could improve the obesity by inhibiting alpha-glycosidase activity.