AIM: To define the age scope of high-risk population for esophageal cancer (EC) in Ci county.METHODS: The results of endoscopic examination of 2013 subjects, cytological screening of 16 763 persons and records of 9 265 patients with EC were analyzed by Ridit methods, the standard age group was 45-49 year group.RESULTS: The average age of patients with moderate esophageal epithelium dysplasia by endoscopic examination was 53.5 years, of severe esophageal epithelium dysplasia,51.4 years, early EC, 55.6 years. The average age of stage one severe epithelium dysplasia (SEEDI) by cytological screening was 51.2 years, of stage two severe epithelium esophageal dysplasia (SEED Ⅱ) 51.6 years, of advanced EC 61.7 years. In the group of 40-year olds,the value of Ridit by pathological diagnosis was 0.46, 95%CI, 0.45-0.47, that by cytological diagnosis was 0.45, 95%CI, 0.43-0.47. As the age increased at five-year intervals,the value of Ridit increased significantly.CONCLUSION: In Ci county of a high incidence area of EC, the age definition of high-risk population should be above 45 years.