【Abstract】Objective To explore the relationship between serum amyloid A (SAA), Creactive protein (CRP) and angiotensinconverting enzyme 2 (ACE2) levels and the severity of acute pancreatitis so as to provide evidence for clinical diagnosis and treatment. Methods A total of 115 patients with acute pancreatitis were selected as the study subjects, and the SAA, CRP and ACE2 levels were detected. The subjects were divided into mild group, moderate group and severe group according to the patient's condition. The SAA, CRP and ACE2 levels, Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) scores and Ranson scores were compared among the 3 groups. Spearman correlation analysis was performed to analyze the correlation between SAA, CRP and ACE2 levels and APACHE Ⅱ score, Ranson score. The ROC curve was used to explore the value of SAA, CRP and ACE2 levels in predicting the severity of acute pancreatitis. Results The order of SAA and CRP levels in the 3 groups from high to low and the order of ACE2 levels from low to high were as follows: severe group, moderate group, mild group (P＜005). The order of APACHEⅡ scores and Ranson scores from high to low was as follows: severe group, moderate group, mild group (P＜005). SAA and CRP levels were significantly positively correlated with APACHE Ⅱ scores and Ranson scores (P＜005). ACE2 levels were significantly negatively correlated with APACHE Ⅱ scores and Ranson scores (P＜005).ROC curve analysis showed that the AUC values of SAA, CRP and ACE2 for predicting moderate to severe acute pancreatitis were 0879, 0823 and 0690, respectively. The sensitivities were 8529%, 7353% and 7059%, respectively. The specificities were 7778%, 8395% and 6667%, respectively. The AUC values of SAA and CRP for predicting moderate to severe acute pancreatitis were larger than those of APACHE Ⅱ scores and Ranson scores (P＜005). Conclusion The SAA, CRP and ACE2 levels are related to the condition of patients with acute pancreatitisThe higher SAA and CRP levels and the lower the ACE2 level, the more serious the patient's condition. Monitor SAA, CRP and ACE2 level can help predict the patients' condition.