Abstract: Objective To study the clinical features of patients with acute pancreatitis（AP） before and after 12 years.Methods Three hundred and twenty-six patients with AP were divided into before 12-year group（n=82） and after 12-year group（n=244）.Their clinical data were analyzed with chi-square test using the CHISS software.Results The visiting rate,pathogenesis,treatment modalities,improvement and complete recovery rate,mortality,average hospital stay time and cost of the patients in the two groups were different.Conclusion The visiting rate,improvement and complete recovery rate and mortality are higher,the average hospital stay time is shorter,and the cost is greater,in patients of after 12-year group than in those of before 12-year group.The diet and hyperlipemia are the pathogenesis of AP.