Abstract: Objective To investigate the etiology and clinical features of acute pancreatitis(AP) in children. Methods A total of 105 children with AP who were admitted to The Affiliated Hospital of Southwest Medical University from January 2013 to December 2018 were enrolled,and according to the severity of AP,they were divided into mild acute pancreatitis(MAP) group with 77 children,moderate-severe acute pancreatitis(MSAP) group with 25 children,and severe acute pancreatitis(SAP) group with 3 children,and a comparative analysis was performed for the MAP group and the MSAP group. According to age,the children were divided into young age group with 36 children aged 2-9 years and old age group with 69 children aged 10-17 years,and according to the presence or absence of recurrence,they were divided into recurrence group with 17 children and non-recurrence group with 88 children; a comparative analysis was also performed. A total of 105 adults with incipient AP were randomly selected from databases and were enrolled as control group,and the groups were compared in terms of general data,etiology,laboratory markers,disease severity,complications,and treatment outcome. The t-test was used for comparison of normally distributed continuous data between groups,and the corrected t-test was used in case of heterogeneity of variance; the Mann-Whitney U test was used for comparison of non-normally distributed data and ranked data between groups; the chi-square test was used for comparison of categorical data between groups; the trend chi-square test was used for unidirectional ordered categorical variables,and a Goodman-Kruskal Gamma analysis was used for bidirectional ordered categorical variables; the Kaplan-Meier method and the log-rank test were used for the comparison of cumulative risk. Results As for etiology,among the 105 children with AP,31(29. 5%) had idiopathic AP,27(25. 7%) had biliary AP,20(19. 0%) had trauma,11(10. 5%) had hyperlipidemic AP,10(9. 5%) had viral infection,and 6(5. 7%) had drug-induced AP,and there was a significant difference in the constituent ratio of etiology between the pediatric patients and the adult patients(χ2= 99. 282,P < 0. 001). Compared with the adult patients,the pediatric patients had significantly lower severity(Z =-2. 325,P < 0. 02) and proportion of individuals with pancreatic necrosis(3. 8% vs 12. 4%,χ2=5. 184,P < 0. 023). Compared with the MSAP group at 24 hours after admission,the MAP group had significantly lower C-reactive protein,blood lipase,white blood cell count,and blood glucose(Z =-6. 406,-3. 096,and-2. 762,t = 3. 298,all P < 0. 05) and a significantly higher blood calcium level(t = 3. 43,P = 0. 001). During follow-up,17 children(16. 2%) developed AP again,and the recurrence rate increased with an increase in disease severity(χ2= 6. 503,P = 0. 011). Recurrent AP was often observed in girls(82. 4%)(χ2= 12. 241,P < 0. 001),and the children with first-onset AP and pancreatic necrosis had a higher recurrence rate(χ2= 6. 572,P =0. 01). Hyperlipidemia was the most common cause of acute recurrent pancreatitis(ARP) in children(χ2= 5. 533,P = 0. 019),and hyperlipidemic AP had the highest risk of recurrence over time,while viral and drug-induced AP had the lowest risk of recurrence(P =0. 028). Conclusion Idiopathic and biliary AP are the main causes of AP in children,and compared with adults,children tend to have milder disease conditions and a better prognosis. Female sex and first-onset AP with pancreatic necrosis and hyperlipidemia are high-risk factors for ARP.