OBJECTIVE To study the therapeutic effects and its mechanism of combination of hemofiltration (HF) and peritoneal dialysis (PD) in the treatment of severe acute pancreatitis (SAP). METHODS Forty patients with SAP were divided at random into the HF + PD group (therapeutic group, 25 patients) and the non-HF + PD group (contrast group, 15 patients). Both groups were treated by the conventional mode of therapy. The release time of abdominal pain and distention, CT scores, APACHE II scores, the time of hospital stay, cost of treatment in hospital, operative rate and rate of complications and recovered rate of the two groups were compared. Simultaneously, the concentration of serum and fluid filtrated pro-inflammatory cytokines TNF, IL-6 and IL-8 were also determined pro and post the therapy. RESULTS The time needed for the disappearance of abdominal pain and the amelioration of abdominal distension, CT scores, APACHE II scores, the average hospital stay and hospital cost of the therapeutic group were significantly decreased compared with those of the contrast group. The cytokines detected at the end of 1d, 2d after HF + PD were decreased significantly compared with those observed in pro HF + PD and the contrast group. CONCLUSIONS The above results show that the cytokines overproduced during the development of SAP can be removed effectively from the circulation and the fluid filtrated by means of HF + PD. The continual deterioration of the local focus and systemtic presentation could be prevented effectively too, and the earlier the treatment of HF + PD, the better the prognosis.