Abstract: To study the effects of space mutated Lactobacillus plantarum SS18-116 on blood lipid in hyperlipidemia rats,48 SPF rats were randomly divided into control group,hyperlipidemia model group,GS18-treated group and SS18-116-treated group. The SPF rats in groups except control were given high-fat diet for 8 w to establish hyperlipidemia rat model. The Wistar rats in control and hyperlipidemia model groups were administrated intragastrical with sterile normal saline,GS18 and SS18-116 groups were given continuous gavage of 8 w at 3.0 mL/kg bw at 10⁹ CFU/mL. The contents of total cholesterol(TC),triglyceride(TG),low-density lipoprotein-cholesterol(LDL-C),and high-density lipoprotein-cholesterol(HDL-C)in serum of rats were determined. Atherosclerosis index(AI)and anti-atherosclerosis index(AAI)were calculated. The results showed that after 8 w of high-fat feeding,the serum TC,TG and LDL-C of the SS18-116 group were significantly reduced compared with those of the high-fat model group and the GS18 group(P<0.05). AI was significantly decreased(P<0.05),while AAI was significantly increased(P<0.05)compared with the high-fat model group. In summary,space mutated L. plantatus SS18-116 had the effect of significantly reducing serum cholesterol and triglyceride in hyperlipidemia rats.