The ways of spreading of esophageal cancer include intramural dissemination, direct infiltration, lymph node metastasis and bloodway metastasis. The mucosa and submucosa of esophagus are rich in lymphatic capillaries, and there is close traffic between lymphatic capillaries, forming a dense lymphatic network. When cancer cells infiltrate the submucosal lymphatic vessels of esophagus, they can infiltrate and spread along the esophageal lamina propria or submucosal lymphatic vessels. The dissemination of cancer cells along the submucosa of the esophagus is not continuous, and the cancer foci formed in the submucosa can be jumping. Therefore, it is very important to resect the appropriate length of esophagus during surgery, otherwise, local recurrence can be caused. The esophagus has no plasma membrane, and the tumor often directly infiltrates the adjacent organs after involving the whole layer of esophagus. Upper esophageal cancer can infiltrate larynx, trachea and soft tissues of neck; middle esophageal cancer can infiltrate bronchus, hilar, innominate vein, odd vein, thoracic duct and thoracic aorta; in advanced stage, it can even penetrate through bronchus to form tracheo-esophageal fistula, or penetrate through aorta to cause perforation resulting in fatal hemorrhage; lower esophageal cancer can infiltrate subpulmonary vein, pericardium, diaphragm or involve cardia. Laboratory general auxiliary examination: routine blood test, fecal occult blood test, biochemical test and immunological test have no special significance in confirming the diagnosis. 2, imaging: ① X-ray barium meal examination: see esophageal peristalsis pause or reverse peristalsis, esophageal wall local stiffness can not be fully dilated, esophageal mucosal disorders, interruption and destruction of esophageal mucosa, esophageal luminal stenosis, irregular filling defects, ulcers or fistula formation. ②CT performance: CT scan can fully show the size of esophageal cancer lesion, the extent and degree of tumor invasion, and it can help surgeons to decide the surgical method and guide the positioning of radiotherapy. 3.Esophagoscopy: the size, shape and location of the tumor can be observed under direct vision, and biopsy or microscopic brushing can be done in the lesion area to clarify the cytopathological diagnosis, which is a decisive means to confirm the diagnosis of esophageal cancer. 4. Pathological and cytological examination: take mucosal biopsy or superficial lymph node biopsy under esophageal microscope for cytopathological examination, and the diagnosis can be confirmed if there are malignant tumor cells.