Reflux esophagitis is mainly clarified by gastroscopy, 24-hour acid test and barium meal imaging. 1. Imaging examination: Reflux esophagitis is mostly due to the relaxation of gastroesophageal sphincter, which leads to a large amount of gastric acid refluxing into the esophagus and damaging the esophageal mucosa, resulting in symptoms such as acid reflux, heartburn and retrosternal pain, etc. Generally speaking, it is necessary to clarify the symptoms through gastroscopy, which can find redness and swelling of the esophageal mucosa, ulceration and erosion. 2. Barium meal imaging of the esophagus: Barium meal imaging of the esophagus can assess swallowing function, esophageal motility, gastroesophageal reflux and morphological abnormalities in the pharynx and esophagus, and it is also a non-invasive and inexpensive procedure that can be widely used without sedation. 3. 24-hour acid test: The presence of abnormal acid reflux is assessed by measuring the change in Ph in the esophagus over a 24-h period.The 24-hour acid test can be an aid in determining the presence of GERD in patients who do not have clinical manifestations of the disease. When a patient with GERD undergoes gastroscopy, it is important to avoid eating for 6 to 8 hours. Gastroscopy before belonging to the fasting state, to avoid the accumulation of food in the stomach to affect the results of the examination.