Objective To evaluate narrow band imaging-magnifying endoscopy (NBI-ME) for the further assessment of lesions of low-grade intraepithelial neoplasia (LGIN) in the gastric biopsy. Methods Data of 180 patients who underwent NBI-ME before endoscopic submucosal dissection (ESD) for biopsy of gastric LGIN at the First Affiliated Hospital of Soochow University from January 2017 to October 2020 were analyzed retrospectively. Taking the pathological results after ESD as the gold standard, the sensitivity, the specificity, the positive predictive value, the negative predictive value, and the accuracy of NBI-ME in predicting the pathological upgrading of gastric LGIN lesions after ESD were calculated, and the receiver operator characteristic (ROC) curve was drawn. Results Among 180 gastric LGIN lesions,115 (63.89%) were pathological upgraded and 65 (36.11%) were not after ESD. There were 10 missed diagnoses, 19 misdiagnoses, and 151 correct diagnoses in NBI-ME examination before ESD. The sensitivity, the specificity, the positive predictive value, the negative predictive value, and the accuracy of NBI-ME in predicting the pathological upgrading of gastric LGIN lesions after ESD were 91.3% (105/115), 70.8% (46/65), 84.7% (105/124), 82.1%(46/56) and 83.9% (151/180), respectively. The area under the ROC curve was 0.810 (95%CI: 0.737-0.883). Conclusion Further NBI-ME examination of gastric LGIN lesions diagnosed by biopsy pathology can accurately predict whether the lesions have pathological upgrading after ESD, which is of important guiding significance for the patients to choose the treatment strategy of further follow-up or endoscopic resection.