Esophageal cancer is one of the most common cancers in China with its high incidence rate and low survival rate. Hence, among all esophageal cancer patients, the incidence of malnutrition is higher than any other types of cancer because of its physiological function and anatomical position. Medical nutritional therapy for patients with esophageal cancer has many advantages, such as reducing postoperative complications, enhancing postoperative recovery, maintaining body weight, preventing muscle loss, and decreasing mortality rates of malnourished patients around surgery. Patients with esophageal cancer may not benefit from routine nutritional therapy. However, when patients with esophageal cancer have moderate to severe swallowing obstruction, weight loss, nutritional risk or their food intake cannot reach more than 60% of the required caloric intake within 3-5 days, nutritional therapy should be then started. An early and timely nutritional therapy should be given to patients, which may improve their nutritional status and reduce the incidence of adverse clinical outcomes, and even benefit the survival of patients. However, the nutritional intervention rate of esophageal cancer patients is low and there is no universal consensus about when and how to properly assess an esophageal cancer patient. And doubts remain about the efficacy of immunonutrition treatment in those patients, with contradictory findings among different clinical trials. To provide clinical reference for improving clinical outcomes of esophageal cancer patients, this article reviews the nutritional status of esophageal cancer patients, the effects of medical nutrition therapy, and the clinical effects of treatment, especially the impact of immunotherapy on patients with esophageal cancer.