Abstract: Objective:To explore the influence of lymph node factors on postoperative radia-tion efficacy in patients with esophageal cancer.Methods 156 patients with esophageal cancer opera-tion were treated with three dimensional conformal radiotherapy.95%PTV =DT:50 to 60 Gy/25 to 30 fx.If shortest diameter of the mediastinal lymph node was greater than 0.8 cm or the margin was posi-tive,then radiation dose increased to 60 Gy.Results The 1,3 and 5 years overall survival rates of 156 esophageal cancer patients with postoperative radiotherapy were 88.5%,57.1% and 46.0% re-spectively.The median survival time was 49.08 months.The 1,3 and 5 years survival rates of lymph node-positive group and lymph node negative group were 8 2 .3 % ,4 7 .8 % ,4 1 .1 % and 9 4 .8 % , 66.9%,50.8% respectively(P =0.049).The 1,3 and 5 years survival rates of one to two positive nodes group and three or more positive lymph nodes group were 88.3%,51.7%,42.7% and 63.2%, 35.5%,35.5% respectively(P =0.028).The 1,3,5 years survival rate of lymph node metastasis rate ≤ 0.15 group and >0.15 group were 93.0%,65.0%,50.3% and 75.6%,35.6%,32.4%respectively(P =0.036).Conclusion The numbers of lymph node metastasis and lymph node me-tastasis rate show a significant influencing on survival rate of esophageal cancer patient with prophylac-tic irradiation.The larger the number of lymph node metastasis is,the lower the survival rate is.Value of concurrent chemoradiotherapy in high-risk postoperative esophageal cancer patients should be ex-plored further.