Abstract： Objective To investigate the effects of dyslipidemia on early insulin secretion in patients with type 2 diabetes mellitus(T2DM). Methods 93 newly diagnosed T2DM patients without lipid-lowering and anti-hyperglycemic therapies were divided into 3 groups: normal lipids (group B),single high triglyceride (group C), and high triglyceride and high total cholesterol with or without low HDL-cholesterol or high LDL-cholesterol (group D).The 20 non-diabetic subjects with normal lipids were healthy control group(group A). Early insulin secretion indexes(ΔI30/ΔG30) and insulin resistance indexes(HOMA-IR) were calculated from oral glucose tolerance test. Results Compared with group A,group B,C and D had a significantly lower ΔI30/ΔG30(P<0.01,<0.05 and<0.05)and a higher HOMA-IR(all P<0.05).In contrast to group B,the group C and D had a significantly lower ΔI30/ΔG30(both P<0.05),and the group D had a significantly higher HOMA-IR(P<0.01) in T2DM groups. But no significant differences in the ΔI30/ΔG30 between group C and D,and in HOMA-IR between group B and C(both P>0.05)were observed. Conclusions High triglyceride reduces early insulin secretion function and cholesterol abnormalities increase insulin resistance in T2DM