Objective To study the relationship between serum adiponectin levels and tumor necrosis factor-α(TNF-α), body mass index(BMI), insulin sensitivity (SI )and some related factors, for clarifying the effects and mechanism of these factors in the ocourrence and development of type 2 diseases mellitus(DM). Methods The levels of adiponectin in 101 normal control subjects and 100 patients with type 2 DM were measured by enzyme linked immunosorbent assay(ELISA). The levels of TNF-α and fasting insulin(FINS) were measured by radioimmunoassay (RIA), fasting blood glucose (FBG)were measured by automatic biochemistry analyer, and their body height and weight were measured for BMI. Results The BMI, levels of FBG, FINS, and insulin resistance(Homa-IR) were significantly higher in type 2 DM group than those in normal control group (P<0.01). The serum adiponectin levels and SI were significantly lower in type 2 DM group than in normal control group(P<0.01). There was no significant difference in the levels of TNF-αbetween type 2 DM group and normal control group(P>0.05). The serum adiponectin levels were positively correlated with SI(P<0.05), and negatively correlated with BMI (P<0.05), and did no correlate with TNF-α(P＞0.05). Conclusions The serum adiponectin levels correlate with SI and BMI, and does no correlate with TNF-α. Adiponectin may play an important role in the occurrence of type 2 DM.