This paper investigated the preventive effects of flavone from hawthorn biloba (FHB) in insulin resistant rats with hyperlipemia, oxidation and fatty liver, and explored the possible mechanisms on enhancing insulin sensitivity and protecting fatty liver. High-fat-sugar diet was fed in rats to produce insulin resistance model. Forty male SD rats were classified into 4 groups randomly: the normal group, the control group, the FHB group and the rosiglitazone group. Then the FHB and the rosiglitazone group were administered for 12 weeks, and blood of the rats was sampled to determin the levels of FFA, TC, TG, HDL-C and T-AOC, and the activities of AST and ALT. As a result, FHB could decrease the levels of FFA and TG, and increase the level of HDL-C, while reduce the activities of ALT, AST and liver index, and reduce the damaged degree of the liver tissue steatosis significantly. FHB also could enhance the activities of SOD and reduce the amount of MDA significantly. Meanwhile, FHB could conspicuously improve the insulin resistance and sensitivity. This work highlights the fact that FHB can regulate actions on hyperlipemia, blood glucose, insulin and oxidation, and improve liver functions of insulin resistant rats induced by high-fat-sugar diet. In addition, FHB can enhance insulin sensitivity, antagonize IR and prevent fatty liver in rats.