In order to clarify the pathological diagnosis, lesion location, early and late stage of disease, the commonly done examinations include fiberoptic gastroscopy, CT examination, barium meal examination of esophagus, etc.. If necessary, tumor standards, magnetic resonance imaging, bone scan, lung function test, etc. are also required. These examinations provide the basis for the next treatment. Fiberoptic gastroscopy is the first choice for patients with dysphagia. A fiberoptic gastroscope is a long, thin tube, about one centimeter in diameter, wrapped in black plastic and containing light-guiding fibers, with an endoscope at the front end, which is inserted through the mouth into the esophagus, stomach, and duodenum to directly observe the mucosa and lesions, and to perform biopsy for pathology and cytology. The detection rate of fiberoptic gastroscopy can reach more than 85%. Some micro lesions can be stained with methylene blue or iodine to increase the detection rate. It is soft and easy to operate, and the patient suffers little pain without fear. Now the painless gastroscopy is carried out, and the patient can do it after a sleep. It is generally tolerated. CT examination i.e. X-ray tomography camera. Intensive CT of neck, chest and abdomen is a routine examination before esophageal cancer treatment. Some patients think that gastroscopy has already confirmed the diagnosis of esophageal cancer, so why do they need to do CT examination? This is because CT can evaluate the local growth of tumor, show the extent of tumor invasion, show the metastasis of neck, mediastinum and abdominal lymph nodes. It shows the presence of lung and liver metastasis. It is very important to decide the next step of treatment. Barium esophageal examination The patient swallows a barium-containing solution that is impervious to X-ray, and the barium is evenly applied to the inside of the esophagus, and the shape of the esophagus is shown under X-ray. The outline of the esophagus and the mucosal image can be observed from different angles, as well as the peristalsis, softness and patency of the esophagus. If necessary, spot films are taken. The main observations are mucosal changes, esophageal mobility, deep ulcers, and esophagotracheal fistula.