Background: Left ventricular ejection fraction (LVEF) is an indicator of heart failure, and it is controversial whether patients with reduced preoperative left ventricular ejection fraction can benefit from heart valve surgery. We aimed to assess the differences in clinical characteristics after surgery in patients with different grades of reduced preoperative LVEF to guide clinical management.Methods: A total of 100 heart valve disease patients with low LVEF (≤50%) who had undergone valve surgery in the Department of Cardiology. The patients were divided into 3 groups according to their LVEF measured by echocardiography before surgery, with LVEF ≤40% as group A, 40%< LVEF ≤45% as group B, and 45%< LVEF ≤50% as group C. Clinical characteristics such as postoperative LVEF values, oxygenation index, liver function and inflammatory index, intra-aortic balloon pump (IABP) utilization rate, and mortality were compared among the three groups of patients.Results: There was no statistically significant difference in the preoperative baseline data between the three groups of patients (P>0.05). The clinical outcomes of patients in group A (n=28) were similar to those of patients in groups B (n=39) and C (n=33) (P>0.05). The vasoactive-inotropic score (VIS), postoperative ventilator use time, length of stay in the care unit, IABP use rate, and mortality rate on the first postoperative day were higher in group A. By comparing the preoperative and postoperative (within 48 hours and 3 months after surgery) cardiac echocardiograms of the 3 groups, we learned that LVEF increased, LV end-systolic internal diameter and LV end-diastolic internal diameter decreased, and ventricular remodeling improved after surgery compared with the preoperative period (P<0.05). The postoperative improvement was more obvious in group A than in groups B and C. Three months after surgery, LVEF increased to 55%, the LV end-systolic internal diameter decreased to 39 mm, and the LV end-diastolic internal diameter decreased to about 55 mm in each group (P>0.05).Conclusions: Patients with heart valve disease and low LVEF should be actively treated with heart valve surgery, which can significantly improve the patient's left ventricular reverse remodeling and cardiac function, thereby facilitating survival.