Objective To evaluate the long-term efficacy and safety of a novel self-help inflatable balloon to prevent esophageal stenosis after extensive endoscopic submucosal dissection (ESD). Methods Patients with early esophageal cancer or precancerous lesions, undergoing ESD in the First Medical Center of Chinese PLA General Hospital from January 2018 to December 2019 were included in the prospective study, who had post-ESD mucosal defect greater than 5/6 of the esophageal circumference and 30-100 mm in length. The self-help inflatable balloon was used to prevent esophageal stenosis after ESD. Mucosal defect of ESD was divided into grade 1 (≥5/6 and less than the whole circumference) and grade 2 (the whole circumference).The incidence of stricture, the time from ESD to the occurrence of stricture, the total number of endoscopic balloon dilations (EBD) or radial incision and cuttings (RIC), and other adverse events were observed. Results A total of 27 patients met the including criteria with follow-up time of 14-38 months, including 3 patients of grade 1 and 24 of grade 2. The ulcer longitudinal length was 73.7±18.4 mm. The time of wearing balloons was 92.0±20.0 days. The overall frequency of stricture was 18.5% (5/27), and the stricture incidence of patients of grade 2 resection was only 16.7% (4/27). The median time from balloon removal to stricture was 17 days. To treat the stricture, two patients received 3 EBD sessions, and three other patients received 2, 1 and 2 RIC sessions, respectively. No balloon was removed in advance, and none had a perforation or delayed bleeding. Conclusion The self-help inflatable balloon shows high efficacy and safety in preventing esophageal stenosis in patients with mucosal defect greater than 5/6 of the esophageal circumference and less than 100 mm in length after extensive esophageal ESD.