Objective To explore the risk factors associated with endoscopic resection beyond expanded indication of undifferentiated early gastric cancer (UD-EGC) patients so as to provide diagnostic evidence for precisely selecting UD-EGC cases in clinical work. Methods Clinical data of patients who underwent endoscopic submucosal dissection (ESD) at Cancer Hospital, Chinese Academy of Medical Sciences, from 2011 to 2018 were reviewed. Patients were divided into expanded indication group and beyond expanded indication group，according to the 4th edition guideline of Japanese Gastric Cancer Association. The endoscopic findings and clinicopathologic characteristics were compared between the groups to identify the risk factors for ESD beyond expanded indication of UD-EGC. Results A total of 158 patients were pathologically confirmed as UD-EGC postoperatively, including 57 patients (36.1%) of expanded indication and 101 patients (63.9%) beyond expanded indication. Multivariate analysis showed endoscopic atrophy type, superficial elevation/depression type, surface redness were significantly associated with beyond expanded indication of UD-EGC. Points of risk scores were assigned for these variables based on the β coefficient as follows: O-type atrophy, 2 points; C-type atrophy, 1 point; superficial elevation/depression type, 1 point; surface redness, 1 point. The risk scoring model showed good discriminatory performance on internal validation (area under the curve：0.796，95%CI：0.726-0.866). Conclusion UD-EGC combined with endoscopic findings such as atrophy, superficial elevation /depression or surface redness shows high possibility of ESD beyond expanded indication. This simple and practical prediction model can provide useful information for endoscopists in selecting UD-EGC patients within ESD expanded indication.