Objective To explore the short-term efficacy of endoscopic submucosal dissection (ESD) in the treatment of early carcinoma in the remnant stomach. Methods A retrospective study was conducted on 45 patients with early residual gastric cancer underwent ESD at the Endoscopy Center of Zhongshan Hospital, Fudan University from December 2014 to April 2024, with a total of 45 lesions. The patients were divided into an anastomotic group (n=15) and a non-anastomotic group (n=30) based on the location of tumor occurrence, and their clinical data, endoscopic diagnosis and treatment, and histopathological conditions were compared between the two groups. Results All 45 patients had lesions with redness and erosion. There were 9 cases of poor lifting of submucosal injection in the anastomotic group and 2 cases in the non-anastomotic group, respectively, and the difference was statistically significant (P<0.05). ESD surgery was performed on 13 lesions in the anastomotic group and 28 lesions in the non-anastomotic group, with surgery times of 80.00 (50.00, 100.00) min and 55.00 (43.75, 80.00) min, respectively. The difference in surgery time between the two groups was statistically significant (P=0.03). Among the 45 patients, ESD surgery achieved curative resection in 35 cases, including 11 cases in the anastomotic group and 24 cases in the non-anastomotic group, with no statistically significant difference. Conclusions Careful preoperative evaluation of early carcinoma in the remnant stomach is essential to prevent oversight. Lesions at anastomotic sites and suture lines present higher technical challenges for complete resection. ESD is safe and effective, with auxiliary traction technique available when necessary.