Abstract： Objective To investigate the characteristics of cardiac structure and function in type 2 diabetes mellitus (DM) with or without hypertension and provide a clinical bases for prevention of cardiac dysfunction. Methods 281 patients were divided into essential hypertension (EH, n =108), type 2 DM ( n =84), and hypertensive DM ( n =89). Color Doppler echocardiogram were measured in all patients. Results Left ventricular mass (LVM) and aortic inner diameter (AO) in hypertensive DM were significantly increased compared with EH and type 2 DM. Left ventricle(LV), interventricular septum (IVS), left atrium(LA) were significantly increased in EH and hypertensive DM compared with type 2 DM. Right ventricular structure was not different among three groups ( P >0.05). The percentage of cardiac systolic and diastolic dysfunction increased significantly in hypertensive DM compared with EH and type 2 DM. Conclusion Changes in cardiac structure and function among type 2 DM, EH and hypertensive DM were markedly different. High blood pressure will promote the damage of cardiac structure and function in hypertensive DM.