Whether the occurrence of gastric ulcer for 20 years will become cancerous or not, it is necessary to distinguish different cases, not every patient with gastric ulcer will become cancerous, even if the occurrence of gastric ulcer with 20 years. The best way is to review gastroscopy regularly and take pathological biopsy if necessary to clarify the nature of gastric ulcer, after all, the risk of gastric ulcer becoming cancerous is less than 1%, but since there is such a risk of becoming cancerous, gastric ulcer should be highly alerted. It should be clarified whether there is H. pylori infection, because H. pylori infection is one of the high-risk factors for gastric cancer. If it is positive, standard quadruple therapy should be adopted to eradicate it in 10-14 days, and regular suppression of gastric acid secretion, use of gastric mucosa-protective drugs and review of gastroscopy should be performed to understand the healing of gastric ulcer.