Abstract:China is a high incidence country of esophageal cancer and gastric cancer, but the detection rate of early upper gastrointestinal tumors is low. The key to early diagnosis and treatment of upper gastrointestinal tumors is high-quality endoscopic diagnosis and treatment of upper gastrointestinal tract. In the process of endoscopic diagnosis and treatment, inadequate mucosal preparation often leads to missed diagnosis and misdiagnosis. At present, there are many guidelines for intestinal preparation methods at home and abroad, but there is no authoritative guideline for upper gastrointestinal mucosal preparation methods. In clinical practice, the preparation methods adopted by different medical institutions are quite different, the mucosal preparation effect is different, and there are still many disputes in some aspects. This paper summarizes the current situation and controversial issues of upper gastrointestinal mucosal preparation at home and abroad, hopes to provide reference for the formulation of clinical norms, and also help to provide ideas for subsequent related research.