Objective: To investigate the relationship between ultrasound derived ratio of femoral vein to femoral artery diameter and hemodynamics in patients with heart failure. Methods: This was a case-control study. A total of 61 patients with heart failure and 49 patients with non-heart failure hospitalized in the Department of Critical Care Medicine from September 2017 to September 2018 were included in this study. Doppler ultrasound was used to measure the femoral artery and vein diameter. After deep inhalation, the femoral vein diameter was measured again, and the ratio of femoral vein and artery diameter was calculated. The central venous pressure (CVP) and mean pulmonary wedge pressure (mPAWP) were also measured. Pearson correlation analysis was used to explore the correlation between the ratio of femoral vein diameter to femoral artery diameter and CVP and mPAWP, and linear regression equation was established. Results: The overall CVP and mPAWP levels were significantly higher, and the femoral vein diameter after deep inhalation was bigger in heart failure patients than in non-heart failure patients(all P<0.001). The femoral vein diameter/femoral artery diameter ratio was positively correlated with CVP (r=0.76, P<0.001), and positively correlated with mPAWP (r=0.40, P<0.001) in heart failure group. The linear regression equation established by the femoral vein/femoral artery diameter ratio and CVP in the heart failure group showed that the inner diameter of the femoral vein/the inner diameter of the femoral artery ratio≥1.3 corresponded CVP≥15.518 cmH₂O(1 cmH₂O=0.098 kPa) in heart failure patients. Conclusions In patients with heart failure, the inner diameter of the femoral vein/femoral artery ratio is positively correlated with CVP and mPAWP. The ratio of inner diameter of the femoral vein/femoral artery can be used to assess the volumetric load of patients with heart failure and to guide the clinical treatment of heart failure patients.