Precancerous lesion is a pathological concept that refers to a category of histological changes that predate the development of carcinoma that are prone to cancer. Gastric carcinogenesis is a multifactorial and multi-stage process. Correa proposed that the evolution of normal gastric mucosa – superficial gastritis – atrophic gastritis – intestinal epithelial metaplasia – heterogeneous hyperplasia – gastric cancer has been recognized by most experts at home and abroad. In 1978, the World Health Organization defined intestinal epithelial hyperplasia and heterogeneous hyperplasia on the basis of atrophic gastritis as precancerous lesions of gastric cancer. After two meetings in Houston and Padova in 1998, experts in gastroenterology and pathology reached a consensus that precancerous lesions of gastric cancer are defined as atrophic gastritis with incomplete intestinal hyperplasia and/or moderate or severe atypical hyperplasia. However, recent data show that the value of intestinal hyperplasia staging to predict gastric cancer is limited, and more emphasis is placed on the range of intestinal hyperplasia. It is now unanimously accepted that heterogeneous hyperplasia (intraepithelial neoplasia) is an important precancerous lesion of the stomach, and it is recognized that as the degree of heterogeneous hyperplasia increases, its cancer rate also increases accordingly. Some studies have shown that: the cancer rate of mild heterogeneous hyperplasia is 2.27%, that of severe hyperplasia is 25.00%, and that of moderate is in between; the relative risk of cancer in mild heterogeneous hyperplasia is 1.97, and the relative risk of cancer in moderate and severe heterogeneous hyperplasia is as high as 26 and 132 times that of the normal population, respectively.