Abstract: Objective To study the role of serum TNF-α level in formation of atherosclerotic plaques. Methods Ten male big ear rabbits were randomly divided into model group (group A, n=5) and normal control group (group B, n=5). After damage to abdominal aorta intima was induced with balloon, the animals in group A were fed with high fat diet for 15 weeks while those in group B were fed with normal diet for 15 weeks. Fasting blood was taken from the ear marginal vein to measure the serum levels of TC, TG, HDL-C, LDL-C and TNF-α before and by the end of week 15. The animals were killed. Their abdominal aorta was isolated and observed under optical microscope. Apoptosis was detected by TUNEL. Results The animal atherosclerosis model was successfully established. The serum levels of TC, TG, LDL-C and TNF-α were significantly higher in group B than in group A (P＜ 0.05). The serum levels of TC, TG and LDL-C were positively related with the serum TNF-α level (P＜ 0.05). However, the serum HDL-C level was not signifcantly related with the serum TNF-α. level. The serum TNF-α level was positively related with the apoptosis index in abdominal aorta plaques. Conclusion TNF-α may be involved in apoptosis in atherosclerotic plaques. Serum levels of TG, TC, LDL-C and TNF-α are the risk factor for atherosclerosis.