To explore the characteristics of cardiac hemodynamics in middleaged and oldaged patients with type 2 diabetes mellitus and the sensitive indicators to determine the early heart diseases by the Lifegard ICG Hemodynamic Monitor. Methods218 individuals were divided into three groups: healthy controls(n=130), patients with prediabetes(n=23), and patients with type 2 diabetes mellitus(n=65). Body mass index (BMI), waisthip ratio (WHR), fasting blood glucose (FPG), triglycerides (TG), total cholesterol (TC), systolic blood pressure (SBP), diastolic blood pressure (DBP), pulse pressure (PP) and mean arterial pressure (MAP) were measured in all subjects. Cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI), stroke volume (SV), stroke index (SI), thoracic fluid content (TFC), acceleration index (ACI), left cardiac works index (LCWI), preejection period (PEP), left ventricular ejection time (LVET), velocity index (VI), contraction time ratio (STR) and heart rate (HR) were measured using the Lifegard ICG Hemodynamic Monitor. Results① There were significant differences in WHR, FPG, TC, SBP, DBP, PP, ACI, VI, PEP and STR in patients with type 2 diabetes mellitus compared with the healthy controls(P<0.05 or P<0.01). ② There were significant differences in FPG, ACI and VI in patients with prediabetes(P<0.05 or P<0.01)compared with the healthy controls. ③ Correlation analysis showed that ACI was negatively related with BMI, WHR, FPG, SBP, DBP, MAP and HR (P<0.01), PEP positively with BMI (P<0.01), VI negatively with BMI, WHR, FPG, SBP, DBP, MAP and HR (P<0.01), and STR positively with BMI and WHR(P<0.05 or P<0.01). ConclusionCardiac hemodynamics impairment exit in patients with diabetes mellitus or prediabetes in various degrees. BMI is a common risk factor to induce the changes of the above indicators. ACI and VI are noninvasive and sensitive indicators in evaluating abnormalities of cardiac hemodynamics in diabetes mellitus.