Objective This study is designed to observe the effects of sodium profile hemodialysis on the relative blood volume and cardiac function. Methods Thirty patients were selected and divided into two groups randomly: conventional hemodialysis (CHD) and profiled hemodialysis (PHD). Relative blood volume (RBV) were observed and recorded every 30 minutes. Cardiac function were tested in the beginning and at the end of the study. Results RBV in both groups decreased gradually, but the loss of RBV is lower in PHD group than in CHD group in two hours of hemodialysis, the difference is significant, P<0.01. Three months later in PHD group, the index of cardiac systolic function: ejection fraction(EF), fractional shortening(FS), peak ejection rate(PER) increased dramatically, the index of cardiac diastolic function artrial filtration fraction (AFF) decreased dramatically, P<0.01. In CHD group, EF, FS didn't change obviously, PER increased, AFF decreased three months later, P<0.05. From this we can see that long-term profiled hemodialysis is helpful to improve the cardiac function of the hemodialysis patients. Conclusion PHD can retain more relative blood volume (RBV) than CHD. A long-term PHD can improve CRF patients' cardiac systolic and diastolic function and is better than CHD. 