Abstract: In this research,to study the hypolipidemic and antioxidant activity of ethanol extracts from Sargassum henslowianum C.Agardh,high and low doses of ethanol extracts from S. henslowianum was obtained by solven extraction. Hypolipidemic and antioxidant activities of extracts of S. Henslowianum in vivo were detected by establishment of acute hyperlipidemia mouse models. The results showed that low doses of extracts from S. henslowianum significantly reduced(p<0.05)the levels of total cholestero(TC),low density lipoprotein-cholestero(LDL)in serum and triglyceride(TG),low density lipoprotein-cholestero(LDL)in liver,but lipoprotein lipase(LPL)activities in serum were increaed(p<0.05);while the high doses increaed significantly contents of high density lipoprotein-cholesterol(HDL)and reduced the levels of low density lipoprotein-cholestero(LDL)in serum,and the levels of triglyceride(TG)in liver(p<0.05). The atherosclerosis index AI1 and AI2 of hyperlipidemia mice were improved significantly by gavage low and high doses of extracts from S. henslowianum(p<0.05). Also,low doses of ethanol extracts of S. henslowianum improved effectively the mice antioxidant levels in vivo,which increased significantly total antioxidant capacity and catalase(CAT),and decreased significantly the content of malondialdehyde(MDA)in liver. So ethanol extracts of S. Henslowianum have potential applications in hypolipidemic and antioxidant.