Although the esophagus can not do general color ultrasound, but for some esophageal lesions, such as for the purpose of clarifying the depth of the esophageal wall invasion by early esophageal tumors can be used to examine the esophagus using a special ultrasound endoscopy. Color ultrasound is a diagnostic technology that uses the principle of Doppler to process the captured blood flow with red, blue, green and other colors and brightness, and superimposed on a two-dimensional ultrasound image. Color ultrasound can be used to examine the heart, gallbladder, spleen, kidneys and other parenchymal organs, as well as the uterus, ovaries, testes, prostate and other parts of the body for cysts and other space-occupying lesions, the function of blood vessels and the state of blood flow, the presence of fluid and the amount of fluid, etc., but it does not have a diagnostic value for esophageal diseases. If symptoms such as acid reflux, heartburn, retrosternal pain, choking sensation, etc. occur, it is suspected to be caused by esophagitis, esophageal cancer, etc. Gastroscopy, esophageal reflux monitoring, esophageal X-ray barium meal, etc. can be examined to find out the cause.