Abstract： Objectives To evaluate the factors that influence the cardiac function in obese and non obese type 2 diabetic patients and to survey the different clinic features between them. Methods 238 type 2 diabetic patients were divided into two groups. QUICKI formula was used for the calculation of insulin sensitivity. The LA (left atria), LVIDd (left ventricular internal diameter), post wall depth of left vetricular(LVPWd), intervetricular septum depth (IVSd), and ejection fraction (EF) were assaied by echocardiography. The ratio of transmitral early to atria peak ( E/A) flow velocity was used as an estimate of diastolic filling and function. Left ventricular mass index(LVMI) was caculated too. Results (1)Clinic features: insulin sensitivity index and high density lipoprotein cholesterol level was lower in obese group compared with non obese group; (2)Cardiac features: LA,LVIDd, LPWDd,LVSd, and LVMI were greater and diastolic filling was decreased in obese group; (3)Multiple liner regression showed that the EF was negatively correlated to LVMI and fasting C peptide(FCP) in obese group, and correlated negatively to LVMI, uric acid(UC), systolic blood pressure (SBP) in nonobese group. The equation was that EF1(obese group)=63.8 0.06 LVMI 0.322 FCP( P value was 0.000, 0.001, 0.046 respectively);EF2(non obese group)=59.3 0.127 LVMI 27.9 UC 0.003 SBP( P value was 0.042, 0.003, 0.021, 0.011, respectively). Conclusion The apparent left ventricular and atria hypertrophy exist in obese group and it coexists with low insulin sensitivity and low high density lipoprotein cholesterol level. The left ventricular hypertrophy (LVH) is the important factor that influences the systolic function of left ventricular in two groups. Besides, there are other factors that regulate the systolic function.