Background: Persistent external pancreatic fistula (EPF) in patients with pancreatic duct disruption or disconnection can result from minimal access to retroperitoneal pancreatic necrosectomy (MARPN) in severe acute pancreatitis patients, which is a difficult problem for clinicians and requires a long treatment duration. This study aimed to investigate the effectiveness and safety of trans-sinus gastric stent placement and drainage using interventional technology in the management of persistent EPF after MARPN in severe acute pancreatitis. Methods: From August 2018 to December 2020, the data of 9 patients with persistent EPF treated with trans-sinus gastric stent placement and drainage in our hospital were retrospectively collected. The main outcome measures were technical success rate, recurrence rate, new pancreatic fluid collection, morbidity, and mortality. All patients were followed up after the procedure through clinic visits and imaging modalities. Results: The median age of the patients was 46 years (30–61 years). The median persistent EPF duration was 5 months (2–12 months). The median follow-up time was 41 months (range, 20–47 months). The median operation time was 48 minutes (range, 40–54 minutes), and the technical success rate was 100%. Seven days after treatment, the percutaneous drainage tubes of all patients were removed. Six months after the procedure, 2 patients lost the stents, and one of those patients suffered from a pseudocyst, which gradually increased to a maximum diameter of 7 cm over 9 months. Therefore, a double pigtail drainage tube was placed under the guidance of an endoscope. The second of these 2 patients had no recurrence or pseudocyst. Twelve months after the procedure, another 3 patients lost the stents; 18 months after the procedure, another 2 patients lost the stents. These patients had no recurrence as well. No other adverse events or deaths occurred during the study period. Conclusion: Trans-sinus tract gastric stent placement and drainage are safe and effective in the treatment of persistent EPF after MARPN in severe acute pancreatitis patients. However, this study had a small sample size and did not include a comparative group.