Endoscopic retrograde appendicitis therapy (ERAT) was developed to diagnose and treat acute appendicitis. This study intended to share our clinical findings and therapeutic experience during its application.One hundred and one retrospective cases were collected for ERAT from January 2015 to April 2018. All clinical features and follow-up were recorded, especially for colonoscopic performance of acute appendicitis, endoscopic retrograde appendicography (ERA), and treatment efficacy.After initial diagnosis via US or CT, colonoscopy visually presented mucosal inflammation around the appendiceal orifice and even pus excretion from the appendiceal orifice. With ERA fluoroscopy, appendix features and appendicitis etiology could be clearly demonstrated, such as fecalith obstruction, appendiceal stenosis, and perforation. Technical success and clinical success of ERAT was 96.0% (97/101) and 97.9% (94/96), respectively. Most surgery was done within 40.0 ± 17.5 minutes and without recorded adverse events. Patients' abdominal pain was immediately relieved within 1.4 ± .9 days. Clinical fever and inflammation were rapidly recovered in 1.6 ± .5 days and 2.3 ± 1.1 days, respectively, after ERAT. Mean postoperative hospital stay was 3.0 ± 1.5 days. Two patients were transferred for appendectomy with continuous abdominal pain after ERAT. Recurrence rate was 13.5% (13/96) during follow-up.ERAT was an alternative and efficient approach for appendicitis diagnosis and treatment.