Esophageal cancer can be detected by gastroscopy. Esophageal cancer belongs to malignant tumor diseases, and its main symptoms are difficulty in swallowing, acid reflux, burning pain in the sternum and so on. Since in the process of gastroscopy, it needs to pass through the esophagus to enter into the stomach, so in this process, the mucosa of the esophagus can be observed at the same time. Once bulging and ulceration are found in the esophagus, part of the tissue can be extracted and examined, so that esophageal cancer can be detected in time. Since the early symptoms of esophageal cancer are not particularly obvious, most people have already entered the middle or late stage when they discover the disease. Apart from gastroscopy, esophageal cancer can also be diagnosed by upper gastrointestinal imaging, which requires patients to take barium sulfate orally and then undergo imaging examination. Once interruption and rigidity of esophageal mucosa are found, one should be alert to esophageal malignant tumor.