Difference of the short diameter of lymph nodes in the main regions of esophageal squamous cell carcinoma (ESCC) and its value in the diagnosis of lymph nodes need to explore. The clinical data of patients with thoracic ESCC who underwent surgical treatment in our hospital were collected. The short diameters of the largest lymph node in each region of the patient were measured by preoperative enhanced computed tomography (CT) and were compared with the postoperative pathology. A total of 477 patients with thoracic ESCC who did not receive neoadjuvant therapy were enrolled in this study. The receiver operating characteristic curve suggested that the short diameters of the paracardial nodes, the left gastric nodes, the right recurrent laryngeal nerve nodes, and the left recurrent laryngeal nerve nodes could well predict the postoperative pathology of the lymph nodes, with area under curve (AUC) of 0.958, 0.937, 0.931, and 0.915, the corresponding cut-off values of 5.7 mm, 5.7 mm, 5.5 mm, and 4.8 mm, the corresponding sensitivities of 94.7%, 85.4%, 88.7%, and 79.4%, and the corresponding specificities of 93.7%, 96.3%, 86.2%, and 95.0%, respectively. The AUC of the thoracic paraesophageal lymph nodes, the subcarinal nodes and all regional lymph nodes were 0.845, 0.688, and 0.776, respectively. Region-based criterion for lymph node metastasis of thoracic ESCC is beneficial to improve the diagnostic efficiency of preoperative CT. © The Author(s) 2023. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: [email protected].