Objective To evaluate the changes of left ventricular global three-dimensional strain in early stage of type 2 diabetes mellitus with real-time three-dimensional echocardiography speckle tracking (RT3D-STI) and to analyze the changes of ascending aorta elasticity, and to explore the relationship between them.Methods Fifty-eight patients with type 2 diabetes mellitus (DM group) were enrolled and 34 healthy subjects were selected as control group. Parameters including global longitudinal strain (GLS), global radial strain (GRS), global circumferential strain (GCS), left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF )and left ventricular mass (LVM) were obtained from cardiac apex full volume images by using RT3D-STI. The parameters of ascending aortic strain (AS), ascending aortic stiffness index (AoSI), ascending aortic dilatation (AoDIS) were calculated by M-mode echocardiography. The brachial artery blood pressure was recorded. And the relationship between the three dimensional strain of the left ventricle and the elastic parameters of the ascending aorta were analyzed. Results: Compared with the control group, the left ventricular GLS, GRS and GCS decreased (P < 0.05), AS and AoDIS decreased (P < 0.05), PP and AoSI increased (P < 0.05) in DM group. And there was weak association between the three dimensional strain of the left ventricle and the elastic parameters of ascending aorta in group DM. Conclusion: RT3D-STI can evaluate the changes of left ventricular systolic function in type 2 diabetes mellitus in early stage. In type 2 diabetes mellitus with normal ejection fraction, the overall three-dimensional strain of left ventricle is decreased and the elasticity of ascending aorta is impaired, and there is a significant but weak correlation between them.