Abstract: Objective To analyze the relationship between the subcarinal lymph node metastasis from middle and lower segment of thoracic esophageal squamous carcinoma and the CT imaging characteristics, to provide certain basis for CT diagnosis. Methods We selected 174 esophageal cancer patients who received operation from 2012 to 2014, and analyzed the relationship between the status and the characteristics of lymph nodes on CT imaging examination. Results There were 4862 lymph nodes cleaned. The average of lymph nodes was (27.94±11.6)/case. Lymph node metastasis number was 306, and transfer rate was 57.47% (100/174), and transfer degree was 6.29%(306/4862). Among them, subcarinal lymph node metastasis rate was 17.24% (30/174) and transfer degree was 6.57% (44/670). The ratio of short-length diameter was related with the shortest diameter in CT(r_s=-0.448, P=0.009; r_s=0.378, P=0.028). It has consistency between CT diagnosis and postoperatively pathological diagnosis of subcarinal lymph node metastasis (Kappa=0.628, P<0.001). The concordance rate was 89.66%, the specificity was 94.44%, the sensitivity was only 66.67%, the misdiagnosis rate was 5.56%, the rate of missed diagnosis was 33.33%, positive predictive value was 71.43%, and negative predictive value was 93.15%. Conclusion (1)It has relationship between subcarinal lymph node metastasis and the ratio of short-length diameter and the shortest diameter in CT. (2)It has consistency between CT diagnosis and postoperatively pathological diagnosis of subcarinal lymph node metastasis.