Esophageal carcinoma is an aggressive disease with a poor prognosis. Surgical resection remains the basic method of management of this malignancy. Although different approaches have been described for the surgical resection of esophageal cancer, there is no statistical evidence based on large scale prospective randomized trials with regard to the issue that which is the optimal surgical approach for esophageal cancer. In middle or lower third intrathoracic esophageal cancer, a great number of thoracic surgeon preferred the Ivor-Lewis Procedure(Right Side Thoracotomy plus Midline Laparotomy Approach), and believe that this approach can get better exposure for the upper mediastinal node dissection so can get the better long-term survival. But some others preferred the Sweet Procedure(Left Side Thoracotomy Approach),especially in china, more than two of the third unit performed the left side approach esophagectomy routinely and the long-term survival was reported equal to even better than the right side approach. The purpose of this study is to conduct a large scale prospective randomized Phase Ⅲ clinical trial to test that based on the long-term outcomes(overall survival and disease free survival )and postoperative short-term outcomes(mortality, morbidity),whether one approach is superior than the other approach or not.