Abstract: Objective To discuss the clinical application value of Tri-plane in measuring left ventricular systolic function in patients with myocardial infarction. Methods Fifty-nine patients with myocardial infarction in our hospital from January to December in 2013 (29 cases with anterial segment infarction, 18 cases with posterial segment infarction, 12 cases with lateral segment infarction) were enrolled in this study, their left ventricular ejection fraction (LVEF) were measured using Tri-plane and Simpson's within one month, the parameters were compared between the two groups and the correlation between the two methods were analyzed. Repeatability study: Twenty patients were randomly selected, their LVEF were detected using Tri-plane by the same observer after two days and then two observers, the correlation between the two methods were analyzed. Results Of the 59 patients, LVEF of 5 cases could not be measured due to the unclear membrane surface display, the correlation of other patients’ LVEF detected by Tri-plane and Simpson's was good with the correlation coefficient of r=0.92. The correlation coefficient of the two methods was 0.83 (P＜ 0.01) and 0.81 (P＜ 0.01), respectively. Conclusion Measuring LVEF with Tri-plane is a simple and accurate method, and it shows good correlation with Simpson's method with good repeatability, which is of great clinical application value.