Abstract: Objective To investigate the risk factors for pathological upgrading after endoscopic treatment of esophageal lesions which confirmed to be low-grade intraepithelial neoplasia (LGIN) by preoperative biopsy. Methods A total of 148 patients who were confirmed to be LGIN in preoperative forceps underwent further endoscopic resection between November 2013 and July 2018. According to the final pathological results after endoscopic treatment, they were divided into pathological upgrading group and pathological non-upgrading group, and their clinicopathological characteristics were analyzed and compared through univariate and multivariate analysis. Results The average age of the patients was (59.95±7.75) years old and the percent of male patients was 67.57% (100/148). Most lesions were located in the middle esophagus (99 cases) and lower esophagus (38 cases). Endoscopic gross type was mainly depressed type (72 cases). The en-bloc resection rate was 99.32% (147/148). Among the patients (77, 52.03%) who had pathological upgrading, 33 (22.3%) cases were HGIN, 25 (16.9%) cases were in-situ cancer, and 19 (12.8%) cases were superficial esophageal squamous cell carcinoma. Univariate analysis showed that circumferential extent (≥1/2), longitudinal diameter (≥3 , submucosa involvement found by endoscopic ultrasongraphy, depressed gross type and redness of lesion mucosa were risk factors for postoperative pathological upgrading. Multivariate analysis indicated that the redness of the lesion mucosa and longitudinal diameter (≥3 of the lesion were independent risk factors for pathological upgrading. Conclusion For esophageal lesions diagnosed by biopsy as LGIN, clinicians should be highly alert to the pathological underestimate if the lesion surface is reddened and its longitudinal diameter is greater than 3 cm.