Objective To evaluate the early changes of left ventricular (LV) diastolic function in patients with diabetes mellitus (DM) by two-dimensional speckle tracking echocardiography. Methods Thirty-six patients with DM and forty-five normal subjects (NOR) were studied. The peak early (E') diastole,peak late (A') diastole of longitudinal strain rate(SrL) in 18 myocardial segments and the average peak E' and A' of SrL on base segments, mid segments, apical segments were measured on apical long-axis views respectively. The global peak E'and A' of circumferential strain rate (SrC), radial strain rate (SrR) and rotation rate (RotR) at three levers were measured on short-axis views respectively. The ratio of E' and A', untwisting rate and untwisting half-time were calculated. At the same time, LV conventional ultrasound parameters were measured. Results Compared with NOR group in SrL,E' of 15/18 segments and E'/A' of 16/18 segments were decreased in DM group,A' of 14/18 segments were increased. The E' of global SrL and SrC, E'/A' of global SrL, SrC and SrR were decreased in DM group. The A' of global SrL, SrC and SrR, E' and E'/A' of global RotR were increased. There was no significant difference in LV conventional ultrasound parameters, untwisting rate and untwisting half-time between DM and NOR groups. Conclusions The decrease of SrL and SrC, increase of RotR and disappearance of myocardial regular movement in SrL and SrR are the early changes of diastolic dysfunction in patients with DM.