Objective To investigate the detection of central venous oxygen saturation ( ScvO2 ) whether can be alternative mixed venous oxygen saturation ( SvO2 ) in elderly patients with acute left ventricular failure.Methods 42 elderly patients with acute heart failure were detected by central venous oxygen saturation and mixed venous oxy-gen saturation before the treatment and 1h,2h,4h after treatment.Then the parameters index changes were analyzed according to the prognosis.Results Whatever the prognosis of the patients were,the trend of ScvO2 and SvO2 was the same.Before the treatment,the blood oxygen saturation detected by the ScvO2 with patients was no statistical differ-ence with the ScvO2(t=0.867,P>0.05),and after treatment of 4h the change trend detected of both has also the consistency,no statistical difference (t=0.681,P>0.05) The correlation coefficient r=0.998,and the relationship between ScvO2 and SvO2 confirmed the same clinical significance.Conclusion Considering the factors of trauma, complications,costs and so on,ScvO2 can be used to replace SvO2 in elderly patients with acute left heart failure.