Abstract: Objective To observe blood plasm omentin level in normal glucose tolerance people and its relevance to obsesity,insulin secretion and blood lipid level. Methods Ninety healthy people who underwent physical examination were allocated into two groups,in which sixty-three people had normal weight(thirty-three men and thirty women) and twenty seven people(twenty-two men and five women) had over weight or obesity.ELASA method was adopted to analyze the blood omentin level.And the relationship between the omentin level with fasting level of lipid,BMI,nsulin level and HOMA-IR were assessed. Results The blood omentin level was lower in over weight or obesity people than that in normal weight people(P<0.05);The blood omentin level was negative in correlation to BMI,HOMA-IR and waistline(adjusting age,sex);The blood omentin level was positive in correlation to HDL(adjusting age, sex); Multiple linear stepwise regression analysis revealed BMI and HOMR-IR were distinct interfering fctors to omentin. Conclusion The blood omentin level is positively correlated to insulin sensitivity.Obesity maybe negatively regulates the expression of omentin gene or prevent it from being released to blood.