Abstract： Objective To investigate the level of 8-iso-prostaglandin F2α（8-iso-PGF2α）and its relationship with insulin resistance in central obese patients with NGT. Methods Two hundred and twenty-two subjects were enrolled and divided into two groups: central obese group (n=123) and normal control group(NC, n=99). The central obese group was subdivided into insulin resistance(IR) group and non-IR group. Serum 8-iso-PGF2α, malondialdehyde (MDA), free fatty acids (FFA), IL-6, TNF-α， and lipid were measured. Results Compared with the control group, the levels of 8-iso-PGF2α(P= 0.001), body mass index(BMI), waist circumference(WC), triglyceride (TG), cholesterol (TC), high density lipoprotein(HDL), FFA, MDA and insulin resistance index (HOMA-IR) significantly increased in obese group(all P<0.05), and they increased even more in IR sub-group than those in non-IR sub-group.The level of 8-iso-PGF2α had independently positive correlation with HOMA-IR. Conclusion Oxidative stress increases in central obese patients with NGT,and it plays an important role in insulin resistance. The level of serum 8-iso-PGF2α is a better parameter indicating the extent of oxidative stress.