Abstract: Objective To research the effects of iod ine excess on serum lipid of rats with expermient auto mimune thyroiditis(EAT)and the interventive effect of different concen trations of selenium.Methods Female Lew is rats were divided into five groupsa trandom:control group,model group,model and excess iodine plus selenium group,model and excessiod ine group,model and excess iodine plus lowse lenium group.The rats were mimuned with pig thyrog lobulin to establish EAT model.The pathological changes of thyroid gland were observed and the levels of thyroid autoan tibody,thyroid hormone and serum lipids in each group were detected.Results The levels of thyroid autoantibo dies and thyroid hormones in all model groups were much higher than those of control group.The level of trigly ceride in model group was lower than that of control group (1.09±0.29 vs 1.93±0.59mmol/L).But high density lipo-protein cholesterolin model group was higher than that of control group(1.23±0.12 vs 0.93±0.21).Compared with model group,thlevels of total cholesterol, low density lipoprote in cholesterol decreased in model and excess iodine group(2.36±0.24,0.92±0.21 vs 2.87±0.10,1.42±0.15mmol/L).For rats fed with different levels of selenium,the levels of serum lipids were decreased with the decrease of selenium in the diet.Conclusion There is an abnormal lipids metablism in EA Trats and EAT rats with excessive iodine.Lowse lenium could increase the adverse effect of thyroid itis and increase the level of lipids under the same high iodine level.