A series of studies has been carried out in Linqu County, Shandong Province, China, a high-risk area for gastric cancer, to investigate the risk factors associated with gastric cancer, precancerous lesions and the prevention of gastric cancer. Our studies showed that sour pancakes (a popular local food), salted foods, cigarette smoking, and family history of gastric cancer were risk factors, whereas fresh vegetables, and intake of vitamin C and calcium were inversely associated with the risk of gastric cancer. The prevalence of chronic atrophic gastritis was approximately 20% in an adult population in Linqu County, intestinal metaplasia was approximately 50%, and dysplasia was approximately 20%. A follow-up study showed that the relative risk of developing gastric cancer increased with the severity of gastric lesions, and was associated with dietary factors, cigarette smoking and H. pylori infection in this population. The findings strongly support the idea that gastric cancer is primarily determined by environmental factors and develops in a multistep progression of precancerous lesions.