Objective:To evaluate the efficacy of modified open necrosectomy (MON) and small incision combined with nephroscopic operation (SINO) in the "one-step" treatment for infected pancreatic necrosis (IPN).Methods:The clinical data of 28 patients with IPN undergoing " one-step" surgery in Hunan Provincial People's Hospital from December 2012 to December 2022 were retrospectively analyzed, including 17 males and 11 females, aged (53.2±13.0) years old. The general information, characteristics of pancreatitis and other clinical data of patients were collected. The white blood cell count, neutrophil count, hematocrit, C-reactive protein (CRP) and other laboratory indicators were compared before and 7 days after surgery. Patients were followed up by outpatient or telephone review.Results:Among the patients, 16 were treated with MON and 12 with SINO. All procedures were successfully completed. Compared to preoperative data, white blood cell count [9.6(6.7, 12.6)×10 9/L vs. 12.7(8.2, 16.6)×10 9/L] and CRP 48.0(25.5, 86.4) mg/L vs. 60.0(23.6, 86.8) mg/L] decreased after surgery (both P<0.05). In MON group, three patients could tolerate fat diet, nine restored physical self-maintenance, and nine returned to occupation after surgery. In SINO group, three patients could tolerate fat diet, six restored physical self-maintenance, and three returned to occupation after surgery. The mortality of 28 patients was 10.7% (3/28). None of patients had incisional hernia. No major complications occurred in MON group. In SINO group, one patient developed new organ failure, two suffered postoperative bleeding requiring intervention, and four suffered new hollow visceral perforation or gastrointestinal fistula. Conclusion:Both MON and SINO are safe and feasible for one-step treatment in patients with IPN.