Abstract： Objective To observe the effects of metformin on the serum levels of adiponectin,interleukin-18(IL-18) and C-reactive protein(C-RP) in overweight/obese type 2 diabetes. Methods The changes of serum levels of HOMA2-IR,adiponectin,IL-18,C-RP and lipid profiles were observed before and after the treatment of metformin. Results After the eight weeks of treatment,the levels of adiponectin and IL-18 were not significantly changed,while C-RP(0.49±0.23 vs 0.89±0.22ng/dl),total cholesterol(TC)(4.58±0.83 vs 6.15±2.23mmol/L),LDL-C(2.65±0.78 vs 3.66±0.84mmol/L) and HOMA2-IR(1.1±0.7 vs 2.3±1.7) were decreased (all P<0.05),HDL-C(1.23±0.30 vs 1.02±0.24mmol/L) was increased (P<0.05). Conclusions Metformin may reduce the serum C-RP level and modulate the disorder of blood lipids,but may have no effect on adiponectin and IL-18