Early gastric cancer screening three items are analyzed as follows: 1. Clinical manifestations, those who have no previous history of gastric disease over 40 years old and present with upper gastrointestinal symptoms or those who have a history of ulcer but the symptoms and pain pattern have changed significantly. 2. Microscopic gastroscopy, microscopic examination can directly observe the site and scope of gastric mucosal lesions, and can clamp small pieces of tissues on suspicious lesions for pathological examination is the most effective method to diagnose gastric cancer, in order to improve the In order to improve the diagnosis rate, 4-6 pieces of biopsy should be taken around the histology of suspicious lesions, and should not be concentrated at one point. 3.Imaging X-ray barium meal examination, the application of digital X-ray gastrointestinal imaging technology has greatly improved the resolution and clarity of the image, which is still a common method to diagnose gastric cancer, and the diagnosis is made through the observation of mucosal phase and filling phase by using dual gas-barium imaging. The disadvantage is that it is not as intuitive as gastroscopy but cannot take biopsy for histological examination. There are other imaging examinations, such as spiral CT, PET-CT gastric fluid exfoliation cytology and tumor markers.