Background: Biliary and hypertriglyceridemic acute pancreatitis (BAP and HTGAP) are two of the leading etiologies in China. Infected pancreatic necrosis (IPN) is a particular and noticeable condition in the late stage of these diseases; however, the influential correlated factors on IPN and how to predict IPN are unclear. Methods: In this retrospective study, 1,116 patients whose diagnosis was BAP or HTGAP met the indusion criteria among 1,746 enrolled cases. Clinical characteristics were carefully recorded for further investigation of the factors influencing IPN. During a 6-month follow-up, we analyzed bacterial spectra and postoperative indicators related to minimally invasive necrosectomy. Results: Gallstones and hypertriglyceridemia were the mast prevalent causes (52.6% vs. 11.3%). The participants with HTGAP were younger (40 vs. 52 years, P<0.001), had a higher rate of severe acute pancreatitis (SAP) (51.8% vs. 32.0%, P<0.001), and had a higher prevalence of multiple organ dysfunction syndrome (MODS) (26.4% vs. 19.0%, P=0.020) than BAP patients. More IPN cases were noted in the BAP group than in the HTGAP group [20.2% vs. 13.7%; odds ratio (OR): 1.598, 95% confidence interval (CI): 1.027 to 2.451; P=0.034]. Etiologies, C-reactive protein (CRP) levels, Acute Physiology and Chronic Health Evaluation II (APACIIE II) scores, and MODS were the factors influencing IPN. The bacterial spectra and the rates of major postoperative complications were not significantly different. Conclusions: Patients with BAP more frequently developed IPN. Etiology was independently related to the occurrence of IPN. The APACHE II score, MODS, etiology, and CRP contributed to predicting IPN occurrence. Management of IPN substantially improved the prognosis.