Objective To investigate the efficacy of additional treatment (chemoradiotherapy or esophagectomy) after endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma. Methods Clinicopathological data of 97 patients of esophageal squamous cell carcinoma with infiltration depth of M3-SM3 who underwent ESD in Zhongda Hospital from July 2014 to April 2019 were reviewed. There were 57 patients in the additional treatment group and 40 patients in the observation group. The rate of relapse‑free survival (RFS) was evaluated by Kaplan‑Meier method (used log‑rank test). Results In the additional treatment group, 15 underwent esophagectomy after ESD, and no tumor metastases were found, but 1 patient died of upper gastrointestinal bleeding after surgery; 42 underwent chemoradiotherapy, and all patients were alive, but 3 patients experienced distant metastases. In the observation group, 13 patients experienced local recurrence, 2 patients died of tumor recurrence and 1 patient died of cerebrovascular disorder. Kaplan‑Meier analysis showed that the RFS rate of the additional treatment group was higher than that of the observation group (P=0.001). Conclusion ESD followed by additional chemoradiotherapy or esophagectomy has good clinical efficacy and can improve prognosis for superficial esophageal squamous cell carcinoma (M3-SM3) patients.