Objective:Velocity Vector Imaging (VVI) was used to evaluate left ventricular diastolic function in patients with different degrees of Metabolic Syndrome (MS) in order to detect changes in left ventricular diastolic function in patients with metabolic syndrome. Methods: 30 healthy medical examiners and 60 patients with metabolic syndrome were selected. According to the different degrees of blood glucose and blood pressure, patients with metabolic syndrome were divided into MS I group and MS II group.All patients were enrolled in a conventional echocardiographic examination of two-dimensional measurement of interventricular septal thickness (IVSd), left ventricular posterior wall end-diastolic thickness (LVPWd), and left ventricular ejection fraction (EF%); PW measurement of diastolic mitral valve blood flow spectrum E peak, A peak; Measurement of early diastolic mitral medial ring spectrum (e’) in TDI mode; Measurement of early peak relaxation velocity (Ve) and peak strain rate (SRe) of left ventricular segments using velocity vector imaging. Results: 1.1 The E/A values of mitral valve flow in MS I group and MS II group were significantly lower than those in the control group (p<0.01), and the difference was statistically significant; There was no significant difference in E/A between MS I and MS II (p>0.05); 1.2 The E/e' values of the medial ring of the mitral valve in MS I and MS II groups were significantly higher than those in the control group (p<0.01). The difference was statistically significant; The E/e' value of MS I group was also significantly higher than that of MS II group (p<0.01). The difference was statistically significant. 2.1 The peak diastolic velocity (Ve) of the left ventricle of MS I group was significantly lower than that of the control group (p<0.01), and the MS II group Ve was significantly lower than the control group except for the ventricular septal apex segment negative (p<0.01). 2.2 The peak strain rate (SRe) of early diastolic in MS I group was lower than that in the control group (p<0.05), and the MS II group SRe was lower than the control group except the middle segment of the posterior septum, the middle segment of the inferior wall and the middle segment of the anterior wall (p<0.05); 2.3 The E/Ve values of the left ventricular long axis mitral annulus in the MS I group and the MS II group were significantly higher than those in the control group (p<0.01), and the E/Ve values in the MS I group were also significantly higher than those in the MS II group. (p<0.01), there is a decreasing trend among the three groups. Conclusions: 1.Determination of early peak diastolic velocity (Ve) and peak strain rate (SRe) in left ventricular segments by VVI technique, can assessment of left ventricular diastolic dysfunction in patients with metabolic syndrome; 2.Patients with metabolic syndrome before the left ventricular structure changes, the E/Ve value can be determined by VVI technique combined with spectral Doppler mitral valve blood flow, which can be used to assess potential left ventricular diastolic dysfunction and distinguish abnormal degree of diastolic function; 3.VVI technology is a non-invasive and simple new method of echocardiography, which can provide a reliable basis for accurate evaluation of left ventricular diastolic function in patients with metabolic syndrome.