Objective To determine the accuracy and influencing factors for endoscopic ultrasound (EUS) in predicting the invasive depth of early gastric cancer (EGC). Methods A retrospective analysis was conducted on data of patients with EGC who were staged T1 with EUS and were treated at Beijing Friendship Hospital from January 2014 to August 2020. The consistency between the invasive depth determined by EUS and postoperative pathology were compared, and the accuracy, the sensitivity and the specificity of EUS were calculated. Logistic regression model was used for univariate and multivariate analysis to explore the relevant factors that affected the accuracy of EUS. Results A total of 380 lesions were included. While 301 intramucosal (T1a) lesions and 79 submucosal (T1b) lesions were detected with EUS, postoperative pathology diagnosed 320 T1a lesions and 60 T1b lesions. The accuracy of EUS in predicting the invasive depth of EGC was 77.1% (293/380), the sensitivity and the specificity were 83.4% (267/320) and 43.3% (26/60) respectively. Multivariate analysis indicated that the lesions located in the upper 1/3 of the stomach (OR=2.272, 95%CI: 1.266-4.080, P=0.006), ≥20 mm in size (OR=2.013, 95%CI: 1.200-3.377, P=0.008) and poorly differentiated cancer (OR=2.090, 95%CI: 1.018-4.294, P=0.045) were the independent risk factors affecting the accuracy of EUS. Poorly differentiated EGC (OR=4.046, 95%CI: 1.737-9.425, P=0.001) was the risk factor for over-staging of EUS. Conclusion EUS is useful in predicting the invasive depth of EGC. Factors affecting the accuracy of EUS include location in the upper 1/3 of the stomach, ≥20 mm in size and poorly differentiated EGC. Additionally, poor differentiation is the risk factor for over-staging of EUS.