I. Examination of esophageal function: 1) esophageal motility test: A) esophageal pressure measurement, for patients suspected of having esophageal motility disorders; B) acid clearance test, to determine the peristaltic efficiency of acid elimination from the body of the esophagus. 2. Gastroesophageal reflux determination: A) acid perfusion test of the esophagus; B) 24-hour esophageal pH monitoring; C) lower esophageal sphincter manometry test. Barium X-ray meal examination: It is one of the important means to diagnose esophageal and cardia tumors, and can provide reliable information for the study of early esophageal cancer, combined with cytology and esophageal endoscopy, it can improve the accuracy of esophageal cancer diagnosis. Barium meal X-ray examination of esophageal cancer not only needs to determine the location, length and obstruction degree of lesions, but also needs to determine whether there is invasion of esophageal lesions and the extent of invasion. 2.CT examination: CT scan can clearly show the relationship between esophagus and adjacent mediastinal organs, but it is difficult to detect early esophageal cancer. Combining CT and X-ray examination can help improve the diagnosis and staging of esophageal cancer. Esophageal exfoliative cytology examination: Esophageal exfoliative cytology examination is simple, convenient, safe, less painful for patients, and with an accuracy rate of more than 90%, which is an important method for mass screening of esophageal cancer. However, it is contraindicated for those with bleeding or bleeding tendency or those with esophageal varices; for those with deep ulcers in esophagus or combined with hypertension, heart disease and late pregnancy, it should be performed with caution; for those with poor general condition or too weak, it should be performed after improving general condition; for those with acute inflammation of upper respiratory tract and upper gastrointestinal tract, it should be performed after controlling infection. In the case of acute inflammation of the upper respiratory tract and upper gastrointestinal tract, the infection should be controlled before the examination. Combined with barium meal X-ray examination, it can be used as a diagnostic basis for esophageal cancer and save most patients from painful esophagoscopy. However, when there is obstruction in esophageal stricture, this method cannot be used and esophagoscopy should be performed. Esophagoscopy: Fiberoptic esophagoscopy has been widely used in the diagnosis of esophageal cancer. Esophagoscopy can directly observe the size, shape and location of tumor to provide clinicians with the basis for treatment, and also can be used for biopsy or mirror brush examination at the lesion site. The combination of esophagoscopy and exfoliative cytology examination is an ideal diagnosis method for esophageal cancer.