Abstract: Objective To analyze the correlation of procalcitonin(PCT) level and severity of acute pancreatitis(AP),and discuss its role in the early prediction of AP. Methods Total 100 cases of AP were enrolled and divided into mild acute pancreatitis group(MAP group) and severe acute pancreatitis group(SAP group),10 healthy subjects were recruited as controls at the same period.The levels of PCT at d1,d3,d5 and d7 after the admission were tested.The acute physiology and chronic health evaluation(APACHE Ⅱ) was performed in all patients within 24 hours.The duration of hospital stay was recorded.The results were analyzed statistically to evaluate the relationship between PCT level and severity of AP. Results The levels of PCT at d1,d3,d5 and d7 in SAP group were significant different from those in MAP and control group(P<0.05),but the difference was not significant between MAP group and control group(P>0.05).There were significant difference in APACHE Ⅱ score,but not in length of stay,between MAP and SAP group.Binary Logistic regression analysis showed that PCT(PCT1,PCT3 and PCT7) level was the risk factor for AP.The odds ratio(OR) for PCT1 were 10.558.The calculated the upper and lower limits were 52.847 and 2.109 at 95%CI for Exp(B). Conclusion The elevated or sustained PCT high level in SAP patients prompts that PCT level play an important role in the early(24 hours) prediction of SAP.