Objective To investigate the diagnostic and therapeutic value of one-time biliopancreatic-duct-imaging-system (eyeMax)-assisted endoscopic retrograde appendicitis therapy (ERAT) for children. Methods A total of 11 children who were diagnosed as having uncomplicated acute appendicitis by imaging in Xi′an Children′s Hospital from August to November 2022 were enrolled. All patients received subscope-assisted ERAT. Subscope was intubated into the appendix cavity to observe the mucosa directly. Appendicitis was treated through cleansing, fecalith extraction, stent drainage. The clinical manifestations under subscope were recorded, as well as the treatment success rate, intubation success rate, the effective rate, complication incidence during and after the operation. Results The age of 11 children was 7.93±2.67 years old. Appendix intubation was successful in all patients. Congestion and swelling of the mucosa in appendiceal orifice and appendix cavity were seen under the subscope in 11 children. There were 6 cases with appendiceal fecaliths, 8 cases with pus and 6 cases with luminal distortion or stenosis. Perforation was observed in 1 case during the operation and no other complication occurred. All patients were treated under subscope, including flushing appendiceal cavity (11 cases), fecalith extraction with extraction basket (3 cases), and appendiceal drainage with stenting (2 cases). The symptoms and signs were relieved after the operation, and the effective rate within 48 hours was 10/11. There were no procedure-related complications or recurrence during postoperative follow-up for 1 week to 4 months. Conclusion Acute appendicitis could be diagnosed by observing the appendix cavity directly under one-time biliopancreatic-duct-imaging-system-assisted ERAT, and also could be treated with the system, where appendix could be preserved and radiation damage could be avoided with safety and effectiveness.