ObjectiveTo explore the relationship between plasma A-FABP and obesity type and degree,glucose and lipid metabolism parameters and insulin sensitivity.MethodsPlasma adipocyte fatty acid binding protein (A-FABP) was detected by double antibody sandwich ELISA in fasting status in subjects with normal glucose regulation and normal weight (NW-NGR,n =44),overweight or obese subjects with normal glucose regulation (OB-NGR,n =36),newly-diagnosed type 2 diabetes mellitus (T2DM) and its subgroups of T2DM with normal weight ( NW-T2DM,n =89 ) and T2D)M with overweight or obesity (OB-T2DM,n =44).And glucose,lipids,insulin levels as well as anthropometrical parameters such as body mass index ( BMI ),fat content ( Fat％ ),waist circumference (WC) and waist hip ratio (WHR) were measured.Meanwhile insulin sensitivity was assessed by HOMA-IR.ResultsAfter age and sex adjustment,plasma A-FABP levels in OB-NGR,NW-T2DM,and OB-T2DM were significantly higher than that of NW-NGR [11.32(6.54 - 15.43)μg/L,14.60(10.35 -20.10) μg/L,18.25(12.85 -26.65) μg/L vs 9.32(3.72 - 14.00) μg/L,all P ＜0.05].There was no difference in plasma A-FABP levels between OB-NGR and NW-T2DM [ 11.32 (6.54 - 15.43 ) vs 14.60 ( 10.35 -20.10) μg/L,P ＞ 0.05 ],but the plasma A-FABP levels in OB-NGR and NW-T2DM were significantly lower than that of OB-T2DM [ 11.32(6.54 - 15.43) μg/L,14.60( 10.35 -20.10) μg/L vs 18.25( 12.85 -26.65 ) μg/L,P ＜0.01 ].In a multiple stepwise regression analysis,HOMA-IR,sex,WC and age were the most significant independent determinants for plasma A-FABP concentration (all P ＜ 0.05 ).Conclusions Plasma A-FABP is strongly associated with the abdominal obesity and insulin resistance,measurement of plasma A-FABP concentrations might be useful for diagnosis of abdominal obesity and type 2 diabetics.