Objective:The purpose of this study is to investigate the relationship between the intervention time and the effect of continuous blood purification(CBP)therapy performed on severe acute pancreatitis(SAP)patients by monitoring the changes of inflammatory cytokines. Methods:A total of 33 SAP patients were hospitalized and treated with CBP therapy. The patients were randomly assigned into three groups(A,B,C)according to the time of CBP therapy performed after the onset of SAP,which is,0~24 h,24~48 h and 48~72 h,respectively. The CBP treatment is continuity veno-venos hemofiltration (CVVHF)for 12 h daily for 3 consecutive days. Blood sample of the patients were collected pre and post CBP therapy. Presence of TNF-α,IL-1,IL-6,IL-8,blood amylase(AMY),C-reactive protein(CRP)and APACHE Ⅱ score were measured and calculated. Results:It showed that the indicators for condition evaluation(AMY,CRP,APACHE Ⅱ score)and the level of inflammatory cytokines (TNF-α,IL-1,IL-6,IL-8),were lower post CBP therapy than that pre CBP therapy in all three groups of SAP patients. The decrease in the indicators for condition evaluation such as AMY,CRP and APACHE Ⅱ score in group C (48~72 h)was statistically lower than those in group A and B (0~24,24~48 h). However,the decrease in the level of inflammatory cytokines such as TNF-α,IL-1,IL-6,and IL-8 was higher in group C(48~72 h)than those in group A and B. Conclusion:CBP therapy can effectively reduce the level of inflammatory cytokines in SAP patients,and also improve their overall condition. SAP patients who received CBP therapy within 48 h show a better improvement in their condition by effectively reducing the level of inflammatory cytokines.