【Abstract】 Objective To analyze the differences of real time three dimensional echocardiography (RT3DE), Mmode echocardiography and two dimensional echocardiography (2DE) for left ventricular function assessment.Methods 55 subjects underwent RT3DE, Mmode echocardiography and 2DE Global LV end diastolic volume (EDV), LV endsystolic volume (ESV), LV ejection fraction (EF), and stroke volume (SV) were measured.Results EDV, ESV and SV by RT3DE were higher than those by 2DE, but which were lower than those by Mmode echocardiography. However, EF by RT3DE was highest whereas lowest by 2DE. EDV, ESV or SV showed significant intraclass correlation for RT3DE, 2DE and Mmode echocardiography. However, there was no significant correlation in EF between by RT3DE and by 2DE or Mmode echocardiography.Conclusion Compared with RT3DE, 2DE significantly underestimated the EDV, ESV and SV, but overestimated EF. Mode echocardiography significantly overestimated the entire four indexes.