Objective To explore the predictive value of the quick sequential organ failure assessment(qSOFA)score combined with red blood cell distribution width-to-serum calcium ratio(RDC)for severe acute pancreatitis(SAP).Methods Clinical data of 319 patients with acute pancreatitis admitted to the Affiliated Hospital of Xuzhou Medical University from June 2018 to October 2022 were retrospectively analyzed,and they were divided into non-SAP group(n=260)and SAP group(n=59).Blood samples were collected and hematologic parameters were measured within 24h of admission.The qSOFA score and bedside index for severity in acute pancreatitis(BISAP)score were performed within 24h of admission.The clinical data between the two groups were compared and the risk factors were analyzed by Logistic regression.The receiver operating characteristic(ROC)curve was used to evaluate the diagnostic value of qSOFA score,RDC and their combined score in predicting SAP.Results Multivariate Logistic regression analysis indicated that RDC(OR=4.111,95％CI:2.053-8.231,P＜0.05)and qSOFA score(OR=9.732,95％CI:3.974-23.832,P＜0.05)were independent risk factors for SAP.The area under the curve(AUC)for the combined score and BISAP score for predicting SAP were 0.915(95％CI:0.872-0.959,P＜0.001),0.839(95％CI:0.782-0.896,P＜0.001),and the sensitivity were 93.2％,66.1％,and the specific-ity were 85.0％,86.2％.Conclusion Both qSOFA score and RDC can predict the occurrence of SAP,and the RDC combined with qSOFA score for predicting SAP has more effectively predictive value,which can be used to early identify the occurrence of SAP,and guide early intervention.