Abstract： Objective： To discuss the effect of free anthraquinone in Radix Polygoni Multiflori Praeparata cum Succo Glycines Sotae on levels of blood lipid in rats with hyperlipidemia and its mechanism. Methods：SD rats were divided into the control group and the modeling group. In the modeling group，the rat models with hyperlipidemia were made by high fat diet and fat emulsion gavage. After successful establishment， the modeling group was divided into the model group， the simvastatin group and the free anthraquinone in Radix Polygoni Multiflori Praeparata cum Succo Glycines Sotae group of lowdose， medium-dose and high-dose(the low-dose，medium-dose and high-dose groups). Each administration group was given corresponding medicines， and the model group and the control group were given saline. After intervention for five weeks，the content of triglyceride(TG)，total cholesterol(TC)，high-density lipoprotein cholesterol(HDL-C) and low-density lipoprotein cholesterol(LDL- C) in serum in rats was detected by blood sampling from femoral artery，and the expression of cathepsin S(CTSS)， superoxide dismutase- 1(SOD1) and superoxide dismutase- 2(SOD2) mRNA in the liver in rats was measured by reverse transcription polymerase chain reaction(RT-PCR) and agarose gel electrophoresis. Results：Compared with that in the control group，the content of TG，TC and LDL- C in the model group was significantly increased(P＜0.01). Compared with that in the model group，the content of TG and LDL-C in the simvastatin group and the low-dose，mediumdose and high- dose groups was significantly decreased(P＜0.05)， and the content of TC in the high- dose group was significantly decreased(P＜0.05). Compared with that in the simvastatin group，the content of TC in the high-dose group was decreased(P＜0.05)， the content of LDL- C was increased. The result of RT- PCR showed that compared with that in the control group，the relative expression of CTSS mRNA in the model group was increased，but there being no significance in the difference，and the relative expression of SOD1 and SOD2 mRNA was significantly decreased(P＜0.05)；compared with that in the model group，the relative expression of SOD1 mRNA in the simvastatin group and the low-dose，medium-dose and high-dose groups was increased(P＜0.05)，and the relative expression of SOD2 mRNA in the simvastatin group and the low-dose group was increased(P＜0.05)；compared with that in the simvastatin group，the expression of SOD2 mRNA in the high- dose group was lower(P＜0.05). Conclusion： Free anthraquinone in Radix Polygoni Multiflori Praeparata cum Succo Glycines Sotae can down-regulate the levels of blood lipid in rats with hyperlipidemia. Its mechanism may be related to the up-regulation of the relative expression of SOD1 and SOD2 mRNA，and the up-regulation of the expression of SOD2 mRNA is the most significant in the low-dose group.