The aim of this study was to investigate the antiobesity and antihyperlipidemic effects of Angelica acutiloba root (Japanese Dong Quai). High-fat diet (HFD)-induced obese rats were treated orally with the polyphenolic-rich extract of Angelica acutiloba root (AARE) once daily for 8 weeks. The AARE (300 mg/kg per day) supplementation significantly lowered body weight gain, visceral fat-pad weights and plasma lipid levels, as well as the coronary artery risk index and the atherogenic index of HFD-fed rats. The AARE caused dose related reductions in the hepatic triglyceride and cholesterol contents, as well as lowered hepatic lipid droplet accumulation and epididymal adipocyte size in the HFD-fed rats. The AARE reversed the HFD-induced down-regulation of the hepatic peroxisome proliferator activated receptor-α (PPARα). The HFD-induced decreases of the hepatic protein level of acyl-CoA oxidase (ACO), and the cytochrome P450 isoform 4A1 (CYP4A1) was up-regulated by AARE. The elevated expressions of hepatic sterol regulatory element binding proteins (SREBPs) of HFD-fed rats were lowered by AARE. These results suggest that AARE attenuated visceral fat accumulation and improved hyperlipidemia in HFD-induced obesity by increasing lipid metabolism through the down-regulation of SREBPs and enhanced the expression of ACO and CYP4A1 in the liver, which was likely mediated by up-regulation of the expression of hepatic PPARα.