Objective To establish new scar‑endoscopic submucosal dissection (scar‑ESD) classification based on the relationship between scars and lesion location under endoscopy, and to explore the clinical efficacy of ESD. Methods Clinical data of 132 patients who underwent ESD with scars from January 2015 to August 2022 at the Digestive Endoscopy Center of Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine. According to the scar‑ESD classification, the lesions without surgical anastomosis at the same location were classified as type A: A0, A1, A2, and A3; and those with surgical anastomosis were classified as type B: B0, B1, and B2. The ESD operation time, specimen size, intraoperative assistant methods, intraoperative perforation, en-bloc resection rate, specimen damage rate, and postoperative complications were recorded for each subtype. Results The age of the 132 patients was 64.22±9.51, with a male-to-female ratio of 3∶1. Forty-nine lesions (37.12%) were located in the esophagus, 40 cases (30.30%) in the stomach, and 43 cases (32.58%) in the colon. The operation time was 49.66±32.96 minutes. The operation time for A0 subtype was 30.38±12.85 minutes, which was significantly shorter than that of the A2 (52.10±36.55 minutes, t=2.15, P<0.05). The operation time for B0 subtype was 45.03±24.35 minutes, which was significantly shorter than that of the B2 (90.71±44.95 minutes, t=3.95, P<0.05). Intraoperative assistance was used in 38 cases (28.79%). Intraoperative perforation occurred in 5 cases (3.79%), including 4 cases of A2 and 1 case of A3, and the highest incidence occurred in the colon [9.30% (4/43)]. The en-bloc resection rate was 97.73% (129/132), the R0 resection rate was 88.64% (117/132), and the curative resection rate was 84.09% (111/132). The specimen damage occurred in 23 cases (17.42%), with the highest incidence in the stomach [32.50% (13/40)]. There were significant differences between A2 and A0 subtypes (t=2.31, P<0.05) in this variable, and between B2 subtype and A0, A1, A2, A3, and B0 subtypes (P<0.05). Conclusion The scar‑ESD classification is beneficial for describing and predicting difficulty of ESD. ESD is still the preferred treatment for early digestive lesions with scars, and the efficacy is satisfactory. But it requires experienced physicians to perform the operation.