Objective：This study aims to evaluate the left ventricular diastolic function in patients with coronary artery disease by three - dimensional speckle tracking imaging(3D - STI). Methods：Sixty - six patients with coronary heart disease were included and divided into two groups according to left ventricular end diastolic pressure(LVEDP)：31 cases in the group with normal left ventricular diastolic function(LVEDP≤ 15 mmhg)，and 35 cases in the group with left ventricular diastolic dysfunction. Thirty healthy volunteers were selected as the control group. The longitudinal strain(LS)，circumferential strain(CS)，area strain(AS)and radial strain(RS)of 17 segments of left ventricular were obtained by 4D auto LVQ software. Results：Four strains of diseased myocardium in left ventricular diastolic dysfunction group was significantly lower than those in normal left ventricular diastolic function group and control group(P ＜ 0.05)，LS and AS of diseased myocardium in normal left ventricular diastolic function group were lower than those in control group(P ＜ 0.05). Pearson correlation analysis showed that the four strains had good correlation with LVEDP(P ＜ 0.001). The analysis of receiver operating characteristic(ROC)curve showed that the area under the curve(AUC)of four strains(LS，CS，AS and RS)predicting left ventricular diastolic dysfunction were 0.76，0.76，0.86 and 0.72 respectively(P ＜ 0.001). Logistic regression analysis revealed that the four strains could be used as risk factors for predicting left ventricular diastolic dysfunction，and their OR values were：LS 9.184(95% CI：1.394~30.496，P=0.021)；CS 7.727(95%CI：1.175~20.841，P=0.033)；AS 8.918(95%CI：1.294~19.484，P=0.022)；RS 7.730 (95%CI：1.344~24.438，P=0.026). Conclusion：3D - STI can be used to evaluate left ventricular diastolic function in patients with coronary artery disease. LS and AS are more useful to find early stage of left ventricular diastolic dysfunction.