Abstract: To explore the effect of sweet potato cellulose particle size on male rats blood lipid,liver lipid. Methods:40 male SD rats were randomly divided into 5 groups,one group as the blank group,the other 4 were divided into high fat control group,group of ordinary cellulose,group of ultrafine cellulose and nano cellulose group.All rats were sacrificed after feeding for 28 days for the determination of lipid in serum and liver index,and total bile acid content of feces and small intestinal juice.Results: High fat control group rats body weight gain,feed intake,blood lipids,liver total fat,total cholesterol( TC),triglyceride( TG) content were significantly higher than those in the blank group,the effect of high fat diet on rat was very obvious. Ordinary cellulose,cellulose group and group of nano cellulose group weight increase weight,blood lipid,liver total fat,total cholesterol,triglyceride content were lower than the high fat control group,at the same time,three cellulose experimental rats defecation amount and total bile acid in feces and intestinal fluid were significantly higher than the high fat control group,showed that the three kinds of different particle size of cellulose could reduce the high fat diet rat liver lipid,total fat,total cholesterol( TC),triglyceride( TG) content. Serum TC,TG,LDL- C concentration was positively correlated with grain and cellulose in hyperlipidemic rats.Reducing cellulose particle size was advantageous to the enhancement of cellulose in lowering blood lipids and liver lipid,and nano cellulose had a good effect on lowering.