【Abstract】 Objective To investigate the efficacy of high volume hemofiltration (HVHF) and continuous venovenous hemodiafiltration (CVVHDF) in the treatment of multiple organ dysfunction syndrome (MODS). Methodology Eighty-five patients with MODS were randomly divided into 2 groups: the HVHF group (n=44), in which the ultrafiltrate rate was set at 4~6L/h and blood flow at 250~300ml/min, and the CVVHDF group (n=41), in which the flow rate of substitution fluid was 2L/h, that of dialysate fluid was 2L/h, and that of blood was 250~300ml/min. Changes of heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), hydrogen ion concentration, HCO3-, oxygenation index (PaO2/FiO2), dose of dopamine administrated, serum creatinine (Scr), BUN, K+, Na+, Ca2+, TNF-α, IL-6, and CRP were compared between the 2 groups before and after the treatment for 24 hours. Mortality rate was compared at the end of the study. Results In HVHF group, 28 cases survived and the mortality rate was 63.6%. In CVVHDF group, 26 cases survived and the mortality rate was 63.4%. There were no differences between the 2 groups. After the treatment, the levels of HR, CVP, Scr and BUN decreased (P<0.05), the dose of dopamine reduced (P<0.05), and the levels of MAP and HCO3 increased (P<0.05), in both groups and without statistical differences between the 2 groups. Electrolyte and acid-base disturbances were corrected in both groups. PaO2/FiO2 increased, and the levels of TNF-α, IL-6, and CRP decreased after the treatment in both groups (P<0.05), as compared with those of before the treatment. However, these changes were more evident in HVHF group than in CVVHDF group (P<0.05). Conclusion Although both HVHF and CVVHDF are effective to excrete extra solutes and water, recover ionic and acid-base balances, and ameliorate tissue hypoxia with little disturbance in blood flow dynamics, HVHF has better abilities in elimination of inflammatory factors and normalization of immune system in MODS patients.