Objective:To evaluate the attenuation corrected(AC) 99m Tc-MIBI gated myocardial perfusion single photon emission tomography (G-SPECT) for the assessment of left ventricular ejection fraction(LVEF). Methods:Total 69 patients probably with coronary artery disease were enrolled in this study. All of them underwent resting G-SPECT and two dimensional echocardiography (2-DE). Left ventricular ejection fraction (LVEF),left ventricular end-diastolic volume(EDV) and left ventricular end-systolic volume (ESV) were acquired from attenuation corrected and non-attenuation corrected (NC) 99mTc-MIBI G-SPECT and 2-DE. T test and correlation analysis were used to compared the parameter of heart function. Results:① EDV and ESV measured by AC and NC G-SPECT were (79.6 ± 33.4) ml and (87.4 ± 34.8) ml (P < 0.01),and (33.8 ± 29.9) ml and (36.7 ± 31.9) ml (P < 0.01). EDV and ESV measured by AC were positively correlated with EDV and ESV measured by NC (rEDV = 0.99,y = 1.04x + 4.73,P < 0.01;rESV = 0.99,y = 1.06x + 0.79,P < 0.01). ② LVEF determined by AC and NC G-SPECT were (60.3 ± 9.2)% and (60.8 ± 9.9)%. No statistical significance was observed between them. However,the positive correlation was found between them(r = 0.98,y = 1.02x-1.04,P < 0.01). ③ LVEF measured by 2-DE was(54.6 ± 8.9)%,which was markedly lower than them determined by AC and NC (P < 0.01). There were positive correlation between them (rNC = 0.88,y = 0.91x + 10.81,P < 0.01;rESV = 0.81,y = 0.87x + 13.10,P < 0.01). Conclusion:LVEF measured by AC G-SPECT,which is accurate and reliable,correlates well with LVEF determined by NC G-SPECT and 2-DE.