Abstract: Objective To explore the correlation of automatic quantification of left ventricular ejection fraction (LVEF) from gated myocardial perfusion SPECT with ^20lTl and rest equilibrium gated blood-pool imaging with ^99mTc-red blood cell. Methods Rest gated myocardial perfusion SPECT with ^20lTl was performed on 72 cases. AUTOQUANT 4.21 software was used to measure LVEF. Rest equilibrium gated blood-pool imaging was also performed within 24 h. The values of LVEF measured by two methods were calculated and compared. Results ① There were strong correlation between the LVEF measured by rest gated myocardial perfusion SPECT and rest equilibrium gated blood-pool imaging(r=0.554, P=0.000). There was no significant difference between the two methods (t=1.194, P>0.05). ② There was no significant difference between the two methods among different disease groups. ③ The values of LVEF measured by two methods were (64.68 ±10.77)% and (62.46±8.99)%. The values of LVEF measured by gated myocardial perfusion SPECT was higher 3.55% than rest equilibrium gated blood-pool imaging. Conclusion There was good correlation between the LVEF measured with gated myocardial perfusion SPECT by AUTOQUANT 4.21 software and gated blood-pool imaging. The LVEF can be accurately evaluated using gated myocardial perfusion SPECT with ^20lTl. The value of LVEF measured by gated myocardial perfusion SPECT was higher than rest equilibrium gated blood-pool imaging.