Histological Node Negative thoracic esophageal squamous cell carcinoma（pN0 ESCC） after radical resection still carries the risk of recurrence after complete surgical resection, especially in some high-risk patients. There are still lack of knowledge on postoperative treatment indication and methods for pN0 ESCC.Our previous study has shown that risk of recurrence is associated with the location and cell differentiation of primary tumor, as well as the presence of lymphovascular invasion. This project is designed to study the efficacy of adjuvant therapies for at patients with pN0 ESCC and above mentioned risk factors of recurrence after radical surgery. We aim to compare the differences among adjuvant chemotherapy, adjuvant radiotherapy, and surgery alone for pN0 ESCC by prospective randomized controlled trial. There has been no similar studies in esophageal cancer previously reported with similar design. The results of this study is expected to have a high clinical relevance.