To explore the effects and mechanisms of Pu-erh tea on hyperlipidemia treatment, antioxidation, vascular endothelium protection and artherosclerosis prevention. Hyperlipidemia were successfully induced in SD rats. Different doses of Pu-erh tea were administered to these rats for 35 days started from the 28th day of induction. Body weights of all animals were recorded during experiment. At the experimental endpoint, blood lipid levels and plasma NO levels were measured. Moreover, aortas of rats were collected to examine patho-histological changes. Results: The comparison on fermenting and fermented Pu-erh tea groups and model group revealed that: (1) Bodyweights were reduced remarkably in Pu-erh tea groups. (2) Levels of TC, TG and LDL-C were decreased and NO content increased significantly in Pu-erh tea groups. (3) Endothelial cells damage was reduced as well as the level of ET-1 in vein. Conclusions: (1) Pu-erh tea can be used as treatment for hyperlipidemia induced by high lipid diet, fermented Pu-erh tea shows a stronger lipid down regulating effect than fermenting Pu-erh tea. (2) Pu-erh tea can protect vascular endothelial cells, and this effect may be associated with increasing plasm levels of NO, and decreasing of ET-1.