Abstract: Abstract Objective: We explored the relationships between 2 diabetes mellitus with Metabolic syndrome and plasma omentin level. Methods: Fasting plasma omentin level of T2DM (forty nine patients with Metabolic syndrome ,forty six patients without Metabolic syndrome) were assayed by enzyme-linked immunosorbent asssy(ELISA), and thirty six controls, The relationship of plasma omentin level with blood glucose,blood lipids, FINs, WHR,BMI,HOMA-IR,SBP,DBP were also analyzed. Results：The plasma omentin level was significantly lower than controls（P<0.01）. Plasma omentin level in T2DM with MS was significantly lower than without MS（P<0.01）.correlation analysis showed that the plasma omentin level was negatively in correlation withWC,TG,HOMA-IR ,Fins,2hPG,FBG,SBP,DBP（r=-0.465，-0.696，-0.648，-0.691，-0.635，-0.380，-0.663，-0.522 P<0.01）, and was positively in correlation with HDL（r= 0.279 P<0.01）.Stepwise regression indicated that BMI,2hPG and WC were independent correlation fators that influenced the level of omentin . Conclusion :Omentin was associated with obesity and insulin resistance in patients with MS. It contributes to the process of MS.

Key words: Omentin, Metabolic syndrome, Type 2 diabetes mellitus.