Abstract： Objective To analyze the rule of lymph node metastasis, compare the preoperative computed tomographic findings with pathological diagnosis in thoracic esophageal carcinoma and to evaluate the clinical value. Methods Six hundred and eighteen patients with esophageal carcinoma after radical resection were enrolled. All patients did not receive any preoperative radiotherapy or chemotherapy, having complete information of postoperative pathological reports. CT scanning were applied to all patients in our hospital. The CT image were transmitted to the three-dimensional treatment planning system via the network at digital format and be reconstructed. In which system the sensitivity, specificity and accuracy rates in diagnosis of lymph node metastasis of the preoperative CT image were observed, measured and recorded. x2 test or Fisdher's statistical methods was adopted for comparing the concord rate of preoperative CT scanning with postoperative pathological diagnosis. Results Lymph nodes metastasis were defected in 242 of the 618 treated patients(39.2%), The rate of lymph node metastasis present in lower neck, upper-mediastinum,middle-mediastinum, lower-mediastinum, and superior abdomen regions in upper-thoracic esophageal carcinoma were 3.2% ,20.8% ,6.4% ,2.4% and 8.0%, in middle-thoracic esophageal carcinoma 1.5%,7.8% ,22.0% ,3.5% and 22.8%, and in lower-thoracic esophageal carcinoma 0% ,2.0% ,21.4% ,6.1% and 32.7%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value,younden index and accuracy rates of diagnosis of lymph node metastasis with preoperative CT scan were 58.3%, 70.7%, 56.2%, 72.5%, 29.0% and 65.9%, respectively. The concordance rate of 0, 1, 2 and ≥ 3 lymph node metastasis by preoperative CT scanning with postoperative pathological diagnosis were 72.4%, 32.2% , 58.3% and 73.1%, respectively in whole group(x2 = 82. 61, P = 0.000). The concordance rate of no lymph node metastasis by CT scan comparing with that by postoperative pathological diagnosis was higher than that of the 1 lymph node metastasis in upper-thoracic esophageal carcinoma 3 lymph node metastasis were 71.1%, 30.1%, 55.6% and 77.8%, respectively(x2 =55.14,P =0.000.Conclusions Preoperative CT image can accurately predict the distribution patterns of the lymph node metastasis in esophageal carcinoma. The concordance rate was the highest in diagnosis of 0 and ≥3 lymph node metastasis, the lowest in diagnosis of one lymph node metastasis. These findings are valuable for definition of the target range of radiotherapy after radical resection of esophageal carcinoma.