Objective:To evaluate different scoring systems in predicting outcome of severe acute pancreatitis(SAP).Methods:A retrospective study was carried out in 168 SAP patients treated in our hospital within the past 10 years. We evaluated the prognostic value of the Sequential Organ Function Assessment (SOFA),Acute Physiology and Chronic Health Evaluation Ⅱ(APACHEII),and Computed Tomography Severity Index(CTSI). The area under a receiver operating characteristic(ROC) curve and univariate and multivariate analysis methods were used.Results:The area under the ROC curve of SOFA,APACHEII,CTSI was 0.846,0.809 and 0.779,respectively. The difference between SOFA and CTSI had statistical significance(Z=2.68,P＜0.01),but the ones between APACHEII and SOFA,CTSI did not have statistical significance(Z=1.079,P＞0.05; Z=0.693,P＞0.05).Univariate analysis showed SOFA, APACHEII, CTSI, age and pancreatic infection were related to prognosis of SAP. Multivariate analysis revealed that only SOFA, APACHEII, CTSI were independent prognosisrelated factors of SAP.Conclusions:SOFA,APACHEII,CTSI all have good predictive ability for prognosis of SAP during dynamic inhospital observation, and combination of the three factors has greater ability for prognosis of outcome of SAP.